Polymeric-inorganic nanoparticle compositions, manufacturing process thereof and their use as lubricant additives

ABSTRACT

The invention relates to polymeric-inorganic nanoparticle compositions and preparation processes thereof. The invention also relates to an additive and lubricant compositions comprising these polymeric-inorganic nanoparticle compositions, as well as to the use of these polymeric-inorganic nanoparticle compositions in an oil lubricant formulation to improve tribological performance, in particular to improve extreme pressure performance and friction reduction on metal parts.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a 35 U.S.C. § 371 U.S. national phase entry ofInternational Application No. PCT/EP2019/051505 having an internationalfiling date of Jan. 22, 2019, which claims the benefit of EuropeanApplication No. 18152958.7 filed Jan. 23, 2018, each of which isincorporated herein by reference in its entirety.

FIELD

The invention relates to polymeric-inorganic nanoparticle compositionsand preparation processes thereof. The invention also relates to anadditive and lubricant composition comprising these polymeric-inorganicnanoparticle compositions, as well as to the use of thesepolymeric-inorganic nanoparticle compositions in an oil lubricantformulation to improve tribological performance, in particular toimprove extreme pressure performance and friction reduction on metalparts.

BACKGROUND

The present invention relates to the field of lubrication. Lubricantsare compositions that reduce friction between surfaces. In addition toallowing freedom of motion between two surfaces and reducing mechanicalwear of the surfaces, a lubricant also may inhibit corrosion of thesurfaces and/or may inhibit damage to the surfaces due to heat oroxidation. Examples of lubricant compositions include, but are notlimited to, engine oils, transmission fluids, gear oils, industriallubricating oils, greases and metalworking oils.

Lubricants typically contain a base fluid and variable amounts ofadditives. Some additives in the lubricant formulation are used toreduce friction and wear between the contacts, which is important forenergy efficiency and durability of the device that is being lubricated.

In recent years, there has been a growing interest in the use of solidinorganic nanoparticles in lubricant formulations. These particles areespecially useful to achieve boundary lubrication and keep surfacesseparated. Studies have shown that the addition of nanoparticles candrastically improve wear and friction performance (Zhou et al,Tribolology Letters 8, 213-218 (2000); Qiu et al. J. Tribol. 123 (3)441-443 (2001).

However, creating a stable dispersion of nanoparticles is problematic.Most untreated inorganic nanoparticles, such as WS₂, TiO₂ and SiO₂, arehydrophilic in nature and therefore form poor dispersions in oil ornon-polar environments. Furthermore, the poor dispersion and weak forcesbetween the particles draw particles together causing agglomeration.These agglomerates will lead to sedimentation that is unwanted andineffective for the formulation.

In order to prevent this sedimentation and enhance dispersion, severaltechniques have been employed. These techniques include for instance theuse of a dispersant moiety in the oil blend. By adding a dispersantmoiety to an oil formulation, dispersion of nanoparticles can beimproved. The dispersion agent or surfactant will have a hydrophilicpart that can interact with the particle's surface and a hydrophobictail that will assist in oil dispersion thereby forming micelles. Oneproblem with the use of dispersant is that a careful equilibrium ofdispersant to particle must exist or the dispersion will fall apart.Heat, energy, and shear forces that are present in a working machine orpart can easily break this equilibrium. The disruption of theequilibrium will lead to sedimentation and agglomeration of particles.Furthermore, dispersant moieties are not suited well for non-polarenvironments. Typically, more polar base fluids need to be added so thatthe dispersant can be compatible. With increasing trends towards morenon-polar fluids (Group III or Group IV oils), many dispersants will notwork well in oil formulations containing these oil.

DE2530002 A1 relates to a method of improving the lubricating propertiesof solid lubricants, especially of molybdenum disulphide. The chemicaland mechanical grafting of polymers or functional organic or inorganicgroups on solids is known. Thus, according to Angew. Makromol. Chemie28, 31 (1973) polymers grafted on various solid fillers to improve inthis way the properties of the fillers. Also, of course, polymers arealready mixed with solids for a variety of applications. However, solidlubricants, and especially molybdenum disulphide, have not yet beentreated by these methods. The disadvantages are the insufficientstability of the particles in oil and the low stress stability of thedispersion under tribological conditions. The disclosed procedurehandles unhealthy and gaseous or at least very volatile compounds and ina very complicated process procedure.

US20140231145 A1 describes inorganic fullerene-like nanoparticles ofmolybdenum disulphide (IF-WS₂) in lubricants with a functionalizingagents, such as amines, silanes, polymers or combinations thereof usingstate-of the art dispersion technologies. The disadvantage is that thedispersions show poor performance in extreme pressure, such as 4-ballweld tests (DIN 51350—part 2).

US2017009171 A1 discloses an industrial lubricant composition includingan oil base and a phosphorus-based non-chlorine additive. The industriallubricant also includes at least one intercalation compound of a metalchalcogenide, a carbon containing compound and a boron containingcompound, wherein the intercalation compound may have a geometry that isa platelet shaped geometry, a spherical shaped geometry, a multi-layeredfullerene-like geometry, a tubular-like geometry or a combinationthereof. The outer layer of the metal chalcogenide might befunctionalized by silanes, amines, monomers, polymer, copolymers andcombination thereof. Dispersions will be prepared using state-of-the-artdispersion technologies. The disadvantage is that the dispersions showpoor performance in extreme pressure, such as 4-ball weld tests (DIN51350—part 2).

WO2014170485 A1 (US2016075965 A1) Lubricant composition comprising atleast one base oil, at least one dispersant having a weight averagemolecular weight higher or equal to 2000 Da and 0.01 to 2 wt % metallicnanoparticles, based on the total weight of the lubricant composition,wherein said metallic nanoparticles are concentric polyhedralnanoparticles with multilayered or sheet structure. The dispersantcomprises also polyacrylates and derivatives thereof. Non-functionalizedpolymer structures are known that under severe conditions stabilityissues might occur resulting in unsatisfying tribological performance.

US 2013/0005619 A1 describes the use of nanoparticles (SiO₂, TiO₂,alumina, and tin oxide) in lubricant formulation in order to reducefriction. In this work, a common dispersing agent, polyisobutenylsuccinimide is used in order to properly disperse the particles.

US 2011/0118156 uses ceramic nanoparticles, specifically SiO₂ with aspecial geometry, to reduce wear and friction. It is also shown that theaddition of these particles helps in the load-bearing capability ofmaterials. In order to disperse the particles, the base oil must bepolar, e.g. water or polar natural oils such as soy bean or palm oil.

Peng et al. (Industrial Lubrication and Tribology, Vol. 62, Issue 2,2010, pages 111-120 or Tribology International, 42, (2009), pages911-917) explain the problem of sedimentation of nanoparticle in oilformulations. Peng et al. treat the surface of the particles with oleicacid. Sedimentation still occurs after some time.

For instance, Böttcher et al. (Polymer Bulletin 44, 223-229, 2000) andGu et al (Journal of Polymer Science, Part A: Polymer Chemistry, 51,2013, 3941-3949) describe the surface initiated polymerization methodusing controlled radical polymerization techniques on SiO₂ and graphenesurfaces. Literature shows that polymers can be added to the surface viasurface initiated polymerization. Just like in the previous examples, asmall molecule is first reacted with the particles surface. Here, themolecule that is attached can react during a polymerization technique.One problem with this method is that crosslinking is likely to occur athigh monomer conversions because of the high density of reactive siteson the particle surface. Another disadvantage to this method is that thepolymer can only be attached at the chain end. Furthermore, if acontrolled polymerization technique such as ATRP is used, thenfiltration of the catalyst is not possible by standard means because theparticle cannot pass through the filter media. Lastly, the controlledpolymerization method is costly and initiator attachment to the particlesurface is tedious.

Battez et al. (Wear 261 (2006) 256-263) describe how ZnO particles in aPAO6 oil formulation can reduce the wear in extreme pressure (EP)conditions. In order to disperse and stabilize the particles, adispersing agent was needed. Here, non-ionic dispersing agentscontaining polyhydroxystearic acid were used (Commercial names of thedispersing agents are Octacare DSP-OL100, and Octacare DSP-OL300). Eventhough a dispersion was created, sedimentation and agglomeration stilloccurred. The authors also showed that a formulation only containing thedispersing agent and base oil can provide a large improvement on wear,and in certain tests outperform the stabilized nanoparticle dispersion.In fact, unstable nanoparticle increased wear.

Extreme pressure additives, or EP additives, are additives forlubricants with a role to decrease or prevent welding of the partsexposed to very high pressures, which would cause a huge damage of themachinery. Extreme pressure additives are usually used in applicationssuch as gearboxes. Extreme pressure gear oils perform well over a rangeof temperatures, speeds and gear sizes to help prevent damage to thegears during starting and stopping of the engine. However, extremepressure additives are rarely used in motor oils, because the sulfur orchlorine compounds contained in them can react with water and combustionbyproducts, forming acids that facilitate corrosion of the engine partsand bearings. Extreme pressure additives typically contain organicsulfur, phosphorus or chlorine compounds, including sulfur-phosphorusand sulfur-phosphorus-boron compounds, which chemically react with themetal surface under high pressure conditions. Under such conditions,small irregularities on the sliding surfaces cause localized flashes ofhigh temperature (300-1000° C.), without significant increase of theaverage surface temperature. The chemical reaction between the additivesand the surface is confined to this area. Extreme pressure additivesmight be for instance dark inactive sulfurized fat, dark activesulfurized fat, dark active sulfur hydrocarbon, short and medium chainchlorinated alkanes or polysulfides. Current trend in the industry is tolower the SAPS (sulfated ash, phosphorus and sulfur) to avoid thedisadvantages described above.

It was therefore an object of the present invention to provide alubricant additive which shows improved extreme pressure andanti-friction performances, while maintaining excellent stability over along period of time in the lubricating oil. This approach indeed avoidsany incompatibilities between different package components, dispersingagents, and other additives in the lubricant formulation and reduces oreven eliminates the SAPS content of the formulation.

SUMMARY

After thorough investigation the inventors of the present invention havesurprisingly found that polymeric-inorganic nanoparticle compositions asdefined as a first aspect of the invention in claim 1 provide improvedextreme pressure and anti-friction performances when added to alubricant composition while being very well dispersed in the lubricationoil.

A second aspect of the invention is a method for manufacturing such apolymeric-inorganic nanoparticle composition.

A third aspect of the invention is the use of such a polymeric-inorganicnanoparticle composition as an additive for a lubricant composition.

A fourth aspect of the invention is a formulation—either as additiveformulation or as ready-to-use lubricant formulation—comprising a baseoil and the polymeric-inorganic nanoparticle composition of theinvention.

DETAILED DESCRIPTION

The Polymeric-Inorganic Nanoparticle Composition According to theInvention

The polymeric-inorganic nanoparticle compositions according to theinvention are characterized in that they are obtainable by milling amixture, the mixture comprising one or more intercalation compound (A)and one or more polymer compound (B),

-   -   (A) wherein the one or more intercalation compound comprises a        metal chalcogenide having molecular formula MX2, where M is a        metallic element selected from the group consisting of titanium        (Ti), vanadium (V), chromium (Cr), manganese (M_(n)), iron (Fe),        cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium        (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium        (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd),        hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium        (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg) and        combinations thereof, and X is a chalcogen element selected from        the group consisting of sulfur (S), selenium (Se), tellurium        (Te), oxygen (0) and combinations thereof.;    -   and    -   (B) wherein the one or more polymer compound is obtainable by        polymerizing a monomer composition comprising:        -   a) one or more functional monomer as component a) selected            from the list consisting of:        -   a1) hydroxyalkyl (meth)acrylates like 3-hydroxypropyl            (meth)acrylate, 3,4-dihydroxybutyl (meth)acrylate,            2-hydroxyethyl (meth)acrylate, 2 hydroxypropyl            (meth)acrylate, 2,5-dimethyl-1,6-hexanediol (meth)acrylate,            1,10 decanediol (meth)acrylate;        -   a2) aminoalkyl (meth)acrylates and aminoalkyl            (meth)acrylamides like            N-(3-dimethyl-aminopropyl)methacrylamide,            3-diethylaminopentyl (meth)acrylate,            3-dibutyl-aminohexadecyl (meth)acrylate;        -   a3) nitriles of (meth)acrylic acid and other            nitrogen-containing (meth)acrylates like            N-(methacryloyloxyethyl)diisobutylketimine,            N-(methacryloyloxyethyl)dihexadecyl-ketimine,            (meth)acryloylamidoacetonitrile,            2-methacryloyloxyethylmethylcyanamide, cyanomethyl            (meth)acrylate;        -   a4) aryl (meth)acrylates like benzyl (meth)acrylate or            phenyl (meth)acrylate, where the acryl residue in each case            can be unsubstituted or substituted up to four times;        -   a5) carbonyl-containing (meth)acrylates like 2-carboxyethyl            (meth)acrylate, carboxymethyl (meth)acrylate,            N-methyacryloyloxy)-formamide, acetonyl (meth)acrylate,            N-methacryloyl-2 pyrrolidinone,            N-(2-methyacryloxyoxyethyl)-2-pyrrolidinone,            N-(3-methacryloyloxy-propyl)-2-pyrrolidinone,            N-(2-methyacryloyloxypentadecyl(-2-pyrrolidinone, N-(3            methacryloyloxyheptadecyl-2-pyrrolidinone;        -   a6) (meth)acrylates of ether alcohols like            tetrahydrofurfuryl (meth)acrylate, methoxyethoxyethyl            (meth)acrylate, 1-butoxypropyl (meth)acrylate,            cyclohexyloxyethyl (meth)acrylate, propoxyethoxyethyl            (meth)acrylate, benzyloxyethyl (meth)acrylate, furfuryl            (meth)acrylate, 2-butoxyethyl (meth)acrylate,            2-ethoxy-2-ethoxyethyl (meth)acrylate,            2-methoxy-2-ethoxypropyl (meth)acrylate, ethoxylated            (meth)acrylates, 1-ethoxybutyl (meth)acrylate, methoxyethyl            (meth)acrylate, 2-ethoxy-2-ethoxy-2-ethoxyethyl            (meth)acrylate, esters of (meth)acrylic acid and methoxy            polyethylene glycols;        -   a7) (meth)acrylates of halogenated alcohols like            2,3-dibromopropyl (meth)acrylate, 4 bromophenyl            (meth)acrylate, 1,3-dichloro-2-propyl (meth)acrylate,            2-bromoethyl (meth)acrylate, 2-iodoethyl (meth)acrylate,            chloromethyl (meth)acrylate;        -   a8) oxiranyl (meth)acrylate like 2, 3-epoxybutyl            (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 10,11            epoxyundecyl (meth)acrylate, 2,3-epoxycyclohexyl            (meth)acrylate, oxiranyl (meth)acrylates such as            10,11-epoxyhexadecyl (meth)acrylate, glycidyl            (meth)acrylate;        -   a9) phosphorus-, boron- and/or silicon-containing            (meth)acrylates like 2-(dimethyl-phosphato)propyl            (meth)acrylate, 2-(ethylphosphito)propyl (meth)acrylate, 2            dimethylphosphinomethyl (meth)acrylate,            dimethylphosphonoethyl (meth)acrylate, diethylmethacryloyl            phosphonate, dipropylmethacryloyl phosphate, 2            (dibutylphosphono)ethyl (meth)acrylate,            2,3-butylenemethacryloylethyl borate,            methyldiethoxymethacryloylethoxysiliane,            diethylphosphatoethyl (meth)acrylate;        -   a10) sulfur-containing (meth)acrylates like            ethylsulfinylethyl (meth)acrylate, 4-thio-cyanatobutyl            (meth)acrylate, ethylsulfonylethyl (meth)acrylate,            thiocyanatomethyl (meth)acrylate, methylsulfinylmethyl            (meth)acrylate, bis(methacryloyloxyethyl) sulfide;        -   a11) heterocyclic (meth)acrylates like 2-(1-imidazolyl)ethyl            (meth)acrylate, oxazolidinylethyl (meth)acrylate,            N-methacryloylmorpholine and 2-(4-morpholinyl)ethyl            (meth)acrylate;        -   a12) maleic acid and maleic acid derivatives such as mono-            and diesters of maleic acid, maleic anhydride, methylmaleic            anhydride, maleinimide, methylmaleinimide;        -   a13) fumaric acid and fumaric acid derivatives such as, for            example, mono- and diesters of fumaric acid;        -   a14) vinyl halides such as, for example, vinyl chloride,            vinyl fluoride, vinylidene chloride and vinylidene fluoride;        -   a15) vinyl esters like vinyl acetate;        -   a16) vinyl monomers containing aromatic groups like styrene,            substituted styrenes with an alkyl substituent in the side            chain, such as alpha-methylstyrene and alpha-ethylstyrene,            substituted styrenes with an alkyl substituent on the ring            such as vinyltoluene and p-methylstyrene, halogenated            styrenes such as monochlorostyrenes, dichlorostyrenes,            tribromostyrenes and tetrabromostyrenes;        -   a17) heterocyclic vinyl compounds like 2-vinylpyridine,            3-vinylpyridine, 2-methyl-5-vinylpyridine,            3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine,            vinylpyrimidine, vinylpiperidine, 9-vinylcarbazole,            3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole,            2-methyl-1-vinylimidazole, N-vinylpyrrolidone,            2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine,            N-vinylcaprolactam, N-vinylbutyrolactam, vinyloxolane,            vinylfuran, vinylthiophene, vinylthiolane, vinylthiazoles            and hydrogenated vinylthiazoles, vinyloxazoles and            hydrogenated vinyloxazoles;        -   a18) vinyl and isoprenyl ethers;        -   a19) methacrylic acid and acrylic acid,    -   and one or both of the components selected from the list        consisting of:        -   b) one or more alkyl (meth)acrylate monomer; and        -   c) the reaction product of one or more ester of            (meth)acrylic acid and one or more hydroxylated hydrogenated            polybutadiene having a number-average molecular weight            (M_(n)) of 500 to 10,000 g/mol,            and wherein the weight ratio of the one or more            intercalation compound (A) to the one or more polymer            compound (B) is 20:1 to 1:5.

Intercalation Compound According to the Invention (Component (A))

The term intercalation compound according to this invention denotes acompound that can be inserted between elements or layers. Theintercalation compound typically has a fullerene-like geometry. The coreof the fullerene-like geometry may be hollow, solid, amorphous, or acombination thereof. A fullerene-like geometry may also be referred toas having a cage geometry. More specifically, in some embodiments, anintercalation compound having an inorganic fullerene-like geometry maybe a cage geometry that is hollow or solid at its core and layered atits periphery. For example, the intercalation compound having theinorganic fullerene like geometry may be a single layer or doublelayered structure. The intercalation compound is not limited on onlysingle layer or double layered structures, as the intercalation compoundmay have any number of layers. These structures are also referred to inthe art as being nested layer structures.

In a preferred embodiment, the inorganic fullerene-like geometry of theintercalation compound may be of spherical, near spherical, polyhedral,elongated, rod-, cube-, sheet- or tube-like geometry or a mixturethereof, with or without a hollow core.

The one or more intercalation compound may have any inorganiccomposition meeting the formula MX₂, where M is a metallic elementselected from the group consisting of titanium (Ti), vanadium (V),chromium (Cr), manganese (M_(n)), iron (Fe), cobalt (Co), nickel (Ni),copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo),technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver(Ag), cadmium (Cd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium(Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg)and combinations thereof, and X is a chalcogen element selected from thegroup consisting of sulfur (S), selenium (Se), tellurium (Te), oxygen(0) and combinations thereof.

According to the present invention, the intercalation compound is amicroscopic particle with at least one dimension being between 2 and 500nm, preferably between 10 and 300 nm and more preferably between 30 and200 nm (determined using transmission electron microscopy, TEM). Thisparticle can either be of individual character or be present in anaggregated and/or agglomerated structure. In these latter cases, thesize of the primary particle is between the aforementioned sizes in atleast one dimension. The above dimensions are provided for illustrativepurposes only, and are not intended to limit the present disclosure.

The intercalation compound having the metal chalcogenide composition,e.g. WS₂, and the fullerene-like geometry may be produced viasulfidization of tungsten oxide nanoparticles in reduction atmosphere ina fluidized bed reactor. The intercalation compound may be formed inaccordance with at least one of the methods disclosed in U.S. Pat. No.6,217,843, U.S. Pat. No. 6,710,020, U.S. Pat. No. 6,841,142, U.S. Pat.No, 7,018,606 and U.S. Pat. No. 7,641,886, which are each incorporatedherein in their entirety. The methods disclosed in the aforementionedpatents are only some examples of methods that are suitable for formingthe intercalation compound. Any method may be employed for forming theabove-described intercalation compound, as long as the compound formedhas a fullerene-like geometry.

In another preferred embodiment, the intercalation compound is ananostructured compound that includes a multi-layered fullerene-likenano-structure composed of a plurality of layers each having a metalchalcogenide composition that has a molecular formula of MX₂ (M=W andX═S), preferably with a spherical shape.

Polymer Compound (Component (B))

In a preferred embodiment of the invention the one or more polymercompound (B) is obtainable by polymerizing a monomer compositioncomprising components a) and b), but not component c), and wherein theone or more polymer compound (B) has a weight-average molecular weight(M_(w)) of 5,000 to 300,000 g/mol, more preferably 10,000 to 200,000g/mol.

In an alternative embodiment of the invention, the above-defined monomercomposition may comprise a monomer mixture as component c) comprisingone or more ester of (meth)acrylic acid and a hydroxylated hydrogenatedpolybutadiene having a number-average molecular weight of 500 to 10,000g/mol. In this context, the polymer compound (B) of this inventioncomprises a first polymer, which is also referred to as backbone or mainchain, and a multitude of further polymers which are referred to as sidechains and are bonded covalently to the backbone. In the present case,the backbone of the polymer is formed by the interlinked unsaturatedgroups of the mentioned (meth)acrylic acid esters. The alkyl groups andthe hydrogenated polybutadiene chains of the (meth)acrylic esters formthe side chains of the polymer. The reaction product of one or moreadditional ester of (meth)acrylic acid and one or more hydroxylatedhydrogenated polybutadiene having a number-average molecular weight of500 to 10,000 g/mol is also referred in the present invention asmacromonomer. If these monomers are included, they are also regarded asmacromonomers for the purpose of calculating the below-mentioned degreeof branching.

In an alternative preferred embodiment of the invention the one or morepolymer compound (B) is obtainable by polymerizing a monomer compositioncomprising components a) and c), and optionally component b), andwherein the one or more polymer compound (B) has a weight-averagemolecular weight (M_(w)) of 10,000 to 1,000,000 g/mol, more preferably50,000 to 1,000,000 g/mol, even more preferably 100,000 to 1,000,000g/mol, most preferably 200,000 to 500,000 g/mol.

In the present invention, molecular weights of the polymers weredetermined by gel permeation chromatography (GPC) using commerciallyavailable polymethylmethacrylate (PMMA) standards. The determination iseffected by GPC with THF as eluent (flow rate: 1 mL/min; injectedvolume: 100 μL).

The number-average molecular weight M_(n) of the macromonomer isdetermined by gel permeation chromatography (GPC) using commerciallyavailable polybutadiene standards. The determination is effected to DIN55672-1 by GPC with THF as eluent.

The one or more polymer compound (B) prepared with a monomer compositioncomprising the components a) and c), and optionally component b), can becharacterized on the basis of its molar degree of branching(“f-branch”). The molar degree of branching refers to the percentage inmol % of macromonomers (component (c)) used, based on the total molaramount of all the monomers in the monomer composition. The molar amountof the macromonomers used is calculated on the basis of thenumber-average molecular weight M_(n) of the macromonomers. Thecalculation of the molar degree of branching is described in detail inWO 2007/003238 A1, especially on pages 13 and 14, to which reference ismade here explicitly.

Preferably, the one or more polymer compound (B) prepared with a monomercomposition comprising the components a) and c), and optionallycomponent b), have a molar degree of branching f_(branch) of 0.1 to 6mol %, more preferably 1 to 4 mol % and most preferably 1.5 to 3 mol %.

The term “(meth)acrylic acid” refers to acrylic acid, methacrylic acidand mixtures of acrylic acid and methacrylic acid; methacrylic acidbeing preferred. The term “(meth)acrylate” refers to esters of acrylicacid, esters of methacrylic acid or mixtures of esters of acrylic acidand methacrylic acid; esters of methacrylic acid being preferred.

According to the invention, the one or more polymer compound (B) asdefined in claim 1 is obtainable by polymerizing a monomer compositioncomprising:

-   -   a) 1 to 60% by weight, preferably 2 to 50% by weight, more        preferably 2 to 40% by weight, most preferably 3 to 35% by        weight, of the one or more functional monomer as component a)        based on the one or more polymer compound (B); and    -   b) 10 to 99% by weight, preferably 20 to 98% by weight, more        preferably 30 to 98% by weight, most preferably 35 to 97% by        weight, of the one or more alkyl (meth)acrylate monomer as        component b) based on the one or more polymer compound (B); and    -   c) 0 to 89% by weight, preferably 10 to 80% by weight, more        preferably 20 to 70% by weight, most preferably 25 to 60% by        weight, the reaction product of one or more ester of        (meth)acrylic acid and one or more hydroxylated hydrogenated        polybutadiene having a number-average molecular weight (M_(n))        of 500 to 10,000 g/mol as component c) based on the one or more        polymer compound (B).

In a preferred embodiment the amount of monomer a), b) and optionally c)of the monomer composition sum up to 100% by weight.

Alkyl (Meth)Acrylates (Component b))

The term “C₁₋₄₀ alkyl (meth)acrylates” refers to esters of (meth)acrylicacid and straight chain, cyclic or branched alcohols having 1 to 40carbon atoms. The term encompasses individual (meth)acrylic esters withan alcohol of a particular length, and likewise mixtures of(meth)acrylic esters with alcohols of different lengths.

According to the invention it is preferred that in component b) of thepolymeric-inorganic nanoparticle composition each of the alkyl group ofthe one or more alkyl (meth)acrylate monomers independently is linear,cyclic or branched and comprises from 1 to 40 carbon atoms.

According to the invention it is also preferred that each of the one ormore alkyl (meth)acrylate monomers independently is

-   -   b1) of formula (I):

-   -   wherein R is hydrogen or methyl, R¹ means a linear, branched or        cyclic alkyl residue with 1 to 8 carbon atoms, preferably 1 to 5        carbon atoms, and more preferably 1 to 3 carbon atoms, or    -   b2) of formula (II):

-   -   wherein R is hydrogen or methyl, R² means a linear, branched or        cyclic alkyl residue with 9 to 15 carbon atoms, preferably 12 to        15 carbon atoms, and more preferably 12 to 14 carbon atoms, or    -   b3) of formula (III):

-   -   wherein R is hydrogen or methyl, R³ means a linear, branched or        cyclic alkyl residue with 16 to 40 carbon atoms, preferably 16        to 30 carbon atoms, and more preferably 16 to 20 carbon atoms.

That is to say, according to the invention, it is preferred that the oneor more alkyl (meth)acrylates as component b) are selected from b1),b2), b3) or a mixture thereof.

The term “C₁₋₈ alkyl (meth)acrylates” refers to esters of (meth)acrylicacid and straight chain or branched alcohols having 1 to 8 carbon atoms.The term encompasses individual (meth)acrylic esters with an alcohol ofa particular length, and likewise mixtures of (meth)acrylic esters withalcohols of different lengths.

According to the invention each of the one or more monomers according toformula (I), i.e. the C₁₋₈ alkyl (meth)acrylates, may independently beselected from the group consisting of (meth)acrylates derived fromsaturated alcohols, preferably methyl (meth)acrylate, ethyl(meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate,n-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl(meth)acrylate, hexyl (meth)acrylate, cycloalkyl (meth)acrylates,cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, heptyl (meth)acrylate, 2-tert-butylheptyl(meth)acrylate, n-octyl (meth)acrylate and 3-isopropylheptyl(meth)acrylate, the most preferred monomer according to formula (II) ismethyl methacrylate.

Particularly preferred C₁₋₈ alkyl (meth)acrylates are methyl(meth)acrylate and n-butyl (meth)acrylate; methyl methacrylate andn-butyl methacrylate are especially preferred.

The term “C₉₋₁₅ alkyl (meth)acrylates” refers to esters of (meth)acrylicacid and straight chain or branched alcohols having 9 to 15 carbonatoms. The term encompasses individual (meth)acrylic esters with analcohol of a particular length, and likewise mixtures of (meth)acrylicesters with alcohols of different lengths.

According to the invention each of the one or more monomers according toformula (II), i.e. the C₉₋₁₅ alkyl (meth)acrylates, may alsoindependently be selected from the group consisting of nonyl(meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl(meth)acrylate, 5-methylundecyl (meth)acrylate, n-dodecyl(meth)acrylate, 2-methyldodecyl (meth)acrylate, tridecyl (meth)acrylate,5-methyltridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, pentadecyl(meth)acrylate, oleyl (meth)acrylate, cycloalkyl (meth)acrylates,cyclohexyl (meth)acrylate having a ring substituent,tert-butylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate,bornyl (meth)acrylate and isobornyl (meth)acrylate.

Particularly preferred C₉₋₁₅ alkyl (meth)acrylates are (meth)acrylicesters of a linear C₁₂₋₁₄ alcohol mixture (C₁₂₋₁₄ alkyl (meth)acrylate).

The term “C₁₆₋₄₀ alkyl (meth)acrylates” refers to esters of(meth)acrylic acid and straight chain or branched alcohols having 16 to40 carbon atoms. The term encompasses individual (meth)acrylic esterswith an alcohol of a particular length, and likewise mixtures of(meth)acrylic esters with alcohols of different lengths.

According to the invention each of the one or more monomers according toformula (III), i.e. the C₁₆₋₄₀ alkyl (meth)acrylates, may alsoindependently be selected from the group consisting of hexadecyl(meth)acrylate, 2-methylhexadecyl (meth)acrylate, heptadecyl(meth)acrylate, 5-isopropylheptadecyl (meth)acrylate,4-tert-butyloctadecyl (meth)acrylate, 5-ethyloctadecyl (meth)acrylate,3-isopropyloctadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl(meth)acrylate, eicosyl (meth)acrylate, cetyleicosyl (meth)acrylate,stearyleicosyl (meth)acrylate, docosyl (meth)acrylate, behenyl(meth)acrylate, eicosyltetratriacontyl (meth)acrylate, cycloalkyl(meth)acrylates, 2,4,5-tri-t-butyl-3-vinylcyclohexyl (meth)acrylate, and2,3,4,5-tetra-t-butylcyclohexyl (meth)acrylate.

Preferably, the C₁₋₄₀ alkyl (meth)acrylates include a mixture of C₁₋₈alkyl (meth)acrylates and C₉₋₁₅ alkyl (meth)acrylates, more preferablyis a C₁₂₋₁₄ alkyl (meth)acrylate.

Hydroxylated Hydrogenated Polybutadienes

The one or more hydroxylated hydrogenated polybutadienes for use ascomponent c) in accordance with the invention have a number-averagemolecular weight M_(n) of 500 g/mol to 10,000 g/mol. Because of theirhigh molecular weight, the hydroxylated hydrogenated polybutadienes canalso be referred to as macroalcohols in the context of this invention.The corresponding esters of (meth)acrylic acid can also be referred toas macromonomers in the context of this invention.

Component c) may comprise a single type of macromonomer or may comprisea mixture of different macromonomers based on different macroalcohols.

By combining a macromonomer as component c) based on a macroalcoholhaving number-average molecular weight of 500 g/mol to 10,000 g/mol withthe one or more compound a) and, optionally, the one or morealkyl(meth)acrylates b) according to the invention, a polymer (B) can beobtained which when combined with the intercalation compound (A) offersa stable well-dispersed polymeric-inorganic nanoparticle composition.

The hydroxylated hydrogenated polybutadiene may be a singlepolybutadiene with a single number-average molecular weight or it may bea mixture of different polybutadienes having different number-averagemolecular weights.

Preferably, the monomer composition comprises as component c) 20 to 60%by weight, more preferably 20 to 50% by weight, even more preferably 20to 45% by weight, most preferably 20 to 35% by weight, of one or moreester of (meth)acrylic acid and one or more hydroxylated hydrogenatedpolybutadiene having a number-average molecular weight of 500 g/mol to10,000 g/mol, based on the total weight of the one or more polymercompound (B).

In the present invention, the expression “based on the one or morepolymer compound (B)” means the same as “based on the total weight ofthe monomer composition”, or “based on the total weight of the one ormore polymer compound (B)”.

Preferably, the one or more hydroxylated hydrogenated polybutadiene ofcomponent c) has a number-average molecular weight of 1,500 to 2,100g/mol, more preferably 1,800 to 2,100 g/mol, most preferably 1,900 to2,100 g/mol.

In another preferred embodiment, the one or more hydroxylatedhydrogenated polybutadiene for use as component c) has a number-averagemolecular weight of 3,500 to 7,000 g/mol, preferably 4,000 to 6,000g/mol, more preferably 4,500 to 5,000 g/mol.

In another preferred embodiment, component c) may be one macromonomerprepared using one or more macroalcohols having different molecularweights, the first macroalcohol having a number-average molecular weightof 1,500 to 2,100 g/mol, more preferably 1,800 to 2,100 g/mol, mostpreferably 1,900 to 2,100 g/mol, and the second macroalcohol having anumber-average molecular weight of 3,500 to 7,000 g/mol, preferably4,000 to 6,000 g/mol, more preferably 4,500 to 5,000 g/mol.

Component c) may also comprise a mixture of two macromonomers, the firstmacromonomer being prepared with a macroalcohol having a number-averagemolecular weight of 1,500 to 2,100 g/mol, more preferably 1,800 to 2,100g/mol, most preferably 1,900 to 2,100 g/mol, and the second macromonomerbeing prepared with a macroalcohol having a number-average molecularweight of 3,500 to 7,000 g/mol, preferably 4,000 to 6,000 g/mol, morepreferably 4,500 to 5,000 g/mol.

According to a preferred embodiment of the present invention, bycombining two macromonomers of different number-average molecularweights, the weight proportion of the lower molecular weightmacromonomer to the higher molecular weight macromonomer is preferablyone or more, more preferably 1.5 to 15, even more preferably 2 to 7,most preferably 3 to 6.

In a preferred embodiment, the hydroxylated hydrogenated polybutadieneis a monohydroxylated hydrogenated polybutadiene, preferably ahydroxyethyl-terminated or hydroxypropyl-terminated hydrogenatedpolybutadiene.

In another preferred embodiment of the invention, the one or more esterof (meth)acrylic acid of the component c) used for the preparation ofthe polymer compound (B) is methyl (meth)acrylate or ethyl(meth)acrylate.

Preferably, the one or more hydroxylated hydrogenated polybutadiene hasa hydrogenation level of at least 99%. An alternative measure of thehydrogenation level which can be determined on the polymer of theinvention is the iodine number. The iodine number refers to the numberof grams of iodine which can be added onto 100 g of polymer. Preferably,the polymer of the invention has an iodine number of not more than 5 gof iodine per 100 g of polymer. The iodine number is determined by theWijs method according to DIN 53241-1:1995-05.

Preferred hydroxylated hydrogenated polybutadienes can be obtainedaccording to GB 2270317.

As used herein, the term “hydroxylated hydrogenated polybutadiene”refers to a hydrogenated polybutadiene that comprises one or morehydroxyl group. The hydroxylated hydrogenated polybutadiene may furthercomprise additional structural units, such as polyether groups derivedfrom the addition of alkylene oxides to a polybutadiene or a maleicanhydride group derived from the addition of maleic anhydride to apolybutadiene. These additional structural units may be introduced intothe polybutadiene when the polybutadiene is functionalized with hydroxylgroups.

Preference is given to monohydroxylated hydrogenated polybutadienes.More preferably, the hydroxylated hydrogenated polybutadiene is ahydroxyethyl- or hydroxypropyl-terminated hydrogenated polybutadiene.Particular preference is given to hydroxypropyl-terminatedpolybutadienes.

These monohydroxylated hydrogenated polybutadienes can be prepared byfirst converting butadiene monomers by anionic polymerization topolybutadiene. Subsequently, by reaction of the polybutadiene monomerswith an alkylene oxide, such as ethylene oxide or propylene oxide, ahydroxy-functionalized polybutadiene can be prepared. The polybutadienemay also be reacted with more than one alkylene oxide units, resultingin a polyether-polybutadiene block copolymer having a terminal hydroxylgroup. The hydroxylated polybutadiene can be hydrogenated in thepresence of a suitable transition metal catalyst.

These monohydroxylated hydrogenated polybutadienes can also be selectedfrom products obtained by hydroboration of (co)polymers of having aterminal double bond (e.g. as described in U.S. Pat. No. 4,316,973);maleic anhydride-ene-amino alcohol adducts obtained by an ene reactionbetween a (co)polymer having a terminal double bond and maleic anhydridewith an amino alcohol; and products obtained by hydroformylation of a(co)polymer having a terminal double bond, followed by hydrogenation(e.g. as described in JP Publication No. S63-175096).

The macromonomers for use in accordance with the invention can beprepared by transesterification of alkyl (meth)acrylates. Reaction ofthe alkyl (meth)acrylate with the hydroxylated hydrogenatedpolybutadiene forms the ester of the invention. Preference is given tousing methyl (meth)acrylate or ethyl (meth)acrylate as reactant.

This transesterification is widely known. For example, it is possiblefor this purpose to use a heterogeneous catalyst system, such as lithiumhydroxide/calcium oxide mixture (LiOH/CaO), pure lithium hydroxide(LiOH), lithium methoxide (LiOMe) or sodium methoxide (NaOMe) or ahomogeneous catalyst system such as isopropyl titanate (Ti(OiPr)₄) ordioctyltin oxide (Sn(OCt)₂O). The reaction is an equilibrium reaction.Therefore, the low molecular weight alcohol released is typicallyremoved, for example by distillation.

In addition, the macromonomers can be obtained by a directesterification proceeding, for example, from (meth)acrylic acid or(meth)acrylic anhydride, preferably under acidic catalysis byp-toluenesulfonic acid or methanesulfonic acid, or from free methacrylicacid by the DCC method (dicyclohexylcarbodiimide).

Furthermore, the present hydroxylated hydrogenated polybutadiene can beconverted to an ester by reaction with an acid chloride such as(meth)acryloyl chloride.

-   -   Preferably, in the above-detailed preparations of the esters of        the invention, polymerization inhibitors are used, for example        the 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl radical and/or        hydroquinone monomethyl ether.

Preferable Monomer Compositions

According to the invention, it is preferred that the one or more polymercompound (B) as defined in claim 1 is obtainable by polymerizing amonomer composition comprising:

-   -   a) 1 to 60% by weight, preferably 2 to 50% by weight, more        preferably 2 to 40% by weight, most preferably 3 to 35% by        weight, of the one or more functional monomer as component a)        based on the one or more polymer compound (B); and    -   b) 10 to 99% by weight, preferably 20 to 98% by weight, more        preferably 30 to 98% by weight, most preferably 35 to 97% by        weight, of the one or more alkyl (meth)acrylate monomer as        component b) based on the one or more polymer compound (B); and    -   c) 0 to 89% by weight, preferably 10 to 80% by weight, more        preferably 20 to 70% by weight, most preferably 25 to 60% by        weight, of the reaction product of one or more ester of        (meth)acrylic acid and one or more hydroxylated hydrogenated        polybutadiene having a number-average molecular weight (M_(n))        of 500 to 10,000 g/mol as component c) based on the one or more        polymer compound (B).

In a preferred embodiment, the amount of monomer a), b) and optionallyc) of the monomer composition sum up to 100% by weight.

According to the invention it is preferred that the one or more polymercompound (B) is obtainable by polymerizing a monomer compositioncomprising:

-   -   a) 1 to 60% by weight, preferably 2 to 50% by weight, more        preferably 2 to 40% by weight, most preferably 3 to 35% by        weight, of the one or more functional monomer as component a)        based on the one or more polymer compound (B); and    -   b) 40 to 99% by weight, preferably 50 to 98% by weight, more        preferably 60 to 98% by weight, most preferably 65 to 97% by        weight, of the one or more alkyl (meth)acrylate monomer as        component b) based on the one or more polymer compound (B);        wherein the amount of all monomers of the monomer composition        sum up to 100% by weight.

According to the invention it is preferred that the one or more polymercompound (B) is obtainable by polymerizing a monomer compositioncomprising:

-   -   a) 1 to 60% by weight, preferably 2 to 50% by weight, more        preferably 2 to 40% by weight, most preferably 3 to 35% by        weight, of the one or more functional monomer as component a)        based on the one or more polymer compound (B); and    -   b1) 0 to 50% by weight, preferably 0 to 40% by weight, more        preferably 0 to 20% by weight, most preferably 0 to 10% by        weight, of the one or more alkyl (meth)acrylate monomer as        component b) based on the one or more polymer compound (B); and    -   b2) 40 to 99% by weight, preferably 50 to 98% by weight, more        preferably 60 to 98% by weight, most preferably 65 to 97% by        weight, of the one or more alkyl (meth)acrylate monomer as        component b) based on the one or more polymer compound (B);        wherein the amount of all monomers of the monomer composition        sum up to 100% by weight.

According to the invention it is preferred that the one or more polymercompound (B) is obtainable by polymerizing a monomer compositioncomprising:

-   -   a) 1 to 60% by weight, preferably 2 to 50% by weight, more        preferably 5 to 40% by weight, most preferably 5 to 25% by        weight, of the one or more functional monomer as component a)        based on the one or more polymer compound (B); and    -   b) 10 to 95% by weight, preferably 20 to 80% by weight, more        preferably 30 to 70% by weight, most preferably 35 to 60% by        weight, of the one or more alkyl (meth)acrylate monomer as        component b) based on the one or more polymer compound (B); and    -   c) 1 to 89% by weight, preferably 10 to 80% by weight, more        preferably 20 to 70% by weight, most preferably 25 to 60% by        weight, of the reaction product of one or more ester of        (meth)acrylic acid and one or more hydroxylated hydrogenated        polybutadiene having a number-average molecular weight (M_(n))        of 500 to 10,000 g/mol as component c) based on the one or more        polymer compound (B);        wherein the amount of all monomers of the monomer composition        sum up to 100% by weight.

According to the invention it is preferred that the one or more polymercompound (B), as defined in claim 1, is obtainable by polymerizing amonomer composition comprising:

-   -   a) 1 to 60% by weight, preferably 2 to 50% by weight, more        preferably 2 to 40% by weight, most preferably 3 to 35% by        weight, of the one or more functional monomer as component a)        selected from the group consisting of monomers a2), a3), a5),        a11), a17) or a mixture thereof, based on the one or more        polymer compound (B); and    -   b) 40 to 99% by weight, preferably 50 to 98% by weight, more        preferably 60 to 98% by weight, most preferably 65 to 97% by        weight, of the one or more alkyl (meth)acrylate monomer as        component b) based on the one or more polymer compound (B);        wherein the amount of all monomers of the monomer composition        sum up to 100% by weight.

According to the invention, it is preferred that the one or more polymercompound (B), as defined in claim 1, is obtainable by polymerizing amonomer composition comprising:

-   -   a2) 1 to 60% by weight, preferably 2 to 50% by weight, more        preferably 2 to 40% by weight, most preferably 3 to 35% by        weight, of the one or more functional monomer a2) as component        a), based on the one or more polymer compound (B); and    -   b) 40 to 99% by weight, preferably 50 to 98% by weight, more        preferably 60 to 98% by weight, most preferably 65 to 97% by        weight, of the one or more alkyl (meth)acrylate monomer as        component b) based on the one or more polymer compound (B);        wherein the amount of all monomers of the monomer composition        sum up to 100% by weight.

In a particularly preferred embodiment of the invention, the one or morepolymer compound (B) is obtainable by polymerizing a monomer compositioncomprising:

-   -   a2) 1 to 10% by weight of an aminoalkyl (meth)acrylamide, most        preferably N-(3-dimethyl-aminopropyl)methacrylamide, as        component a) based on the one or more polymer compound (B);    -   b1) 0 to 10% by weight of an alkyl (meth)acrylate monomer of        formula (I), most preferably methyl methacrylate, as first        component b) based on the one or more polymer compound (B);    -   b2) 80 to 99% by weight of an alkyl (meth)acrylate monomer of        formula (II), most preferably lauryl methacrylate, as        component b) based on the one or more polymer compound (B);        wherein the amount of all monomers of the monomer composition        sum up to 100% by weight.

In a particularly preferred embodiment of the invention the one or morepolymer compound (B) is obtainable by polymerizing a monomer compositioncomprising:

-   -   a2) 1 to 10% by weight of an aminoalkyl (meth)acrylamide, most        preferably N-(3-dimethyl-aminopropyl)methacrylamide, as        component a) based on the one or more polymer compound (B); and    -   b2) 90 to 99% by weight of an alkyl (meth)acrylate monomer of        formula (II), most preferably lauryl methacrylate, as        component b) based on the one or more polymer compound (B);        wherein the amount of all monomers of the monomer composition        sum up to 100% by weight.

In another particularly preferred embodiment of the invention the one ormore polymer compound (B) is obtainable by polymerizing a monomercomposition comprising:

-   -   a2) 1 to 10% by weight of an aminoalkyl (meth)acrylamide, most        preferably N-(3-dimethyl-aminopropyl)methacrylamide, as        component a) based on the one or more polymer compound (B);    -   b1) 1 to 10% by weight of an alkyl (meth)acrylate monomer of        formula (I), most preferably methyl methacrylate, as first        component b) based on the one or more polymer compound (B); and    -   b2) 80 to 98% by weight of an alkyl (meth)acrylate monomer of        formula (II), most preferably a C₁₂-C₁₅ methacrylate, as second        component b) based on the one or more polymer compound (B);        wherein the amount of all monomers of the monomer composition        sum up to 100% by weight.

According to the invention it is preferred that the one or more polymercompound (B) is obtainable by polymerizing a monomer compositioncomprising:

-   -   a) 1 to 60% by weight, preferably 2 to 50% by weight, more        preferably 5 to 40% by weight, most preferably 5 to 25% by        weight, of the one or more functional monomer as component a)        selected from the group consisting of monomers a2), a3), a5),        a11), a16), a17) or a mixture thereof, based on the one or more        polymer compound (B); and    -   b) 10 to 95% by weight, preferably 20 to 80% by weight, more        preferably 30 to 70% by weight, most preferably 35 to 60% by        weight, of the one or more alkyl (meth)acrylate monomer as        component b) based on the one or more polymer compound (B); and    -   c) 1 to 89% by weight, preferably 10 to 80% by weight, more        preferably 20 to 70% by weight, most preferably 25 to 60% by        weight, of the reaction product of one or more ester of        (meth)acrylic acid and one or more hydroxylated hydrogenated        polybutadiene having a number-average molecular weight (Mn) of        500 to 10,000 g/mol as component c) based on the one or more        polymer compound (B);        wherein the amount of all monomers of the monomer composition        sum up to 100% by weight.

In yet another particularly preferred embodiment of the invention theone or more polymer compound (B) is obtainable by polymerizing a monomercomposition comprising:

-   -   a2) 0.5 to 5% by weight of an aminoalkyl (meth)acrylamide, most        preferably N-(3-dimethyl-aminopropyl)methacrylamide, as first        component a) based on the one or more polymer compound (B);    -   a16) 5 to 20% by weight of a vinyl monomer containing aromatic        groups, most preferably styrene, as second component a) based on        the one or more polymer compound (B);    -   b1) 25 to 60% by weight of an alkyl (meth)acrylate monomer of        formula (I), most preferably methyl methacrylate and/or butyl        methacrylate, as first component b) based on the one or more        polymer compound (B);    -   b2) 1 to 10% by weight of an alkyl (meth)acrylate monomer of        formula (II), most preferably lauryl methacrylate, as second        component b) based on the one or more polymer compound (B); and    -   c) 25 to 60% by weight of an ester of a (meth)acrylic acid and a        hydroxylated hydrogenated polybutadiene having a number-average        molecular weight (M_(n)) of 500 to 10,000 g/mol, most preferably        a macromonomer derived from the reaction of an ester of a        (meth)acrylic acid and a hydroxylated hydrogenated polybutadiene        having a number-average molecular weight (M_(n)) of 1,500-5,000        g/mol, as component c) based on the one or more polymer compound        (B);        wherein the amount of all monomers of the monomer composition        sum up to 100% by weight.

In another preferred embodiment, the polymeric-inorganic nanoparticlecomposition, obtainable by milling a mixture, corresponds to the mixturecomprising one or more intercalation compound (A) and one or morepolymer compound (B),

-   -   being the intercalation compound (A) a nanostructured compound        that includes a multi-layered fullerene-like nano-structure        composed of a plurality of layers each having a metal        chalcogenide composition and with a molecular formula of MX2        (M=W and X′S), preferably with a spherical shape,    -   and the compound (B) being prepared with one of the above        preferred monomer compositions.

Preparation of the Polymer Compound (B)

According to the present invention, the above-mentioned polymers may beprepared following the method comprising the steps of:

-   -   (a) providing a monomer composition as describe above; and    -   (b) initiating radical polymerization in the monomer        composition.

Standard free-radical polymerization is detailed, inter alia, inUllmann's Encyclopedia of Industrial Chemistry, Sixth Edition. Ingeneral, a polymerization initiator and optionally a chain transferagent are used for this purpose.

The polymerization can be conducted under standard pressure, reducedpressure or elevated pressure. The polymerization temperature is alsouncritical. In general, however, it is in the range from −20 to 200° C.,preferably 50 to 150° C. and more preferably 80 to 130° C.

The polymerization step (b) may be performed with or without dilution inoil. If dilution is performed, then the amount of the monomercomposition, i.e. the total amount of monomers, relative to the totalweight of the reaction mixture is preferably 20 to 90% by weight, morepreferably 40 to 80% by weight, most preferably 50 to 70% by weight.

Preferably, the oil used for diluting the monomer mixture is an APIGroup I, II, III, IV or V oil, or a mixture thereof. Preferably, a GroupIII oil or a mixture thereof is used to dilute the monomer mixture.

Preferably, step (b) comprises the addition of a radical initiator.

Suitable radical initiators are, for example, azo initiators, such asazobis-isobutyronitrile (AIBN), 2,2′-azobis(2-methylbutyronitrile)(AMBN) and 1,1-azobiscyclohexanecarbonitrile, and peroxy compounds suchas methyl ethyl ketone peroxide, acetylacetone peroxide, dilaurylperoxide, tert-butyl per-2-ethylhexanoate, ketone peroxide, tert-butylperoctoate, methyl isobutyl ketone peroxide, cyclohexanone peroxide,dibenzoyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxyisopropylcarbonate,2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane, tert-butylperoxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate,dicumyl peroxide, 1,1-bis(tert-butylperoxy)cyclohexane,1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, cumylhydroperoxide, tert-butyl hydroperoxide and bis(4-tert-butylcyclohexyl)peroxydicarbonate.

Preferably, the radical initiator is selected from the group consistingof 2,2′-azobis(2-methylbutyronitrile), 2,2-bis(tert-butylperoxy)butane,tert-butylperoxy 2-ethylhexanoate,1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexan, tert-butylperoxybenzoate and tert-butylperoxy-3,5,5-trimethylhexanoat.Particularly preferred initiators are tert-butylperoxy 2-ethylhexanoateand 2,2-bis(tert-butylperoxy)butane.

Preferably, the total amount of radical initiator relative to the totalweight of the monomer mixture is 0.01 to 5% by weight, more preferably0.02 to 1% by weight, most preferably 0.05 to 0.6% by weight.

The total amount of radical initiator may be added in a single step orthe radical initiator may be added in several steps over the course ofthe polymerization reaction. Preferably, the radical initiator is addedin several steps. For example, a part of the radical initiator may beadded to initiate radical polymerization and a second part of theradical initiator may be added 0.5 to 3.5 hours after the initialdosage.

Preferably, step (b) also comprises the addition of a chain transferagent. Suitable chain transfer agents are especially oil-solublemercaptans, for example n-dodecyl mercaptan or 2-mercaptoethanol, orchain transfer agents from the class of the terpenes, for exampleterpinolene. Particularly preferred is the addition of n-dodecylmercaptan.

It is also possible to divide the monomer composition into an initialpart and a second part and to add a part of the radical initiator to theinitial part only to start the polymerization reaction therein. Then,the second part of the radical initiator is added to the second part ofthe monomer composition which is then added over the course of 0.5 to 5hours, preferably 1.5 to 4 hours, more preferably 2 to 3.5 hours, to thepolymerization reaction mixture. After addition of the second monomermixture, a third part of the radical initiator may be added to thepolymerization reaction as described above.

Preferably, the total reaction time of the radical polymerization is 2to 10 hours, more preferably 3 to 9 hours.

After completion of the radical polymerization, the obtained polymer ispreferably further diluted with the above-mentioned oil to the desiredviscosity. Preferably, the polymer is diluted to a concentration of 5 to60% by weight polymer, more preferably 10 to 50% by weight, mostpreferably 20 to 40% by weight.

The Polymeric-Inorganic Nanoparticle Composition of the Invention andPreparation Process Thereof

According to the invention in the polymeric-inorganic nanoparticlecomposition, the weight ratio of the one or more intercalation compound(A) to the one or more polymer compound (B) is 20:1 to 1:5, preferably10:1 to 1:2, more preferably 5:1 to 1:1, most preferably 4:1 to 2:1.

According to a preferred embodiment of the invention, thepolymeric-inorganic nanoparticle composition is obtainable by milling amixture, the mixture comprising one or more intercalation compound (A)and one or more polymer compound (B),

-   -   wherein the intercalation compound (A) is a nanostructured        compound that includes a multi-layered fullerene-like        nano-structure composed of a plurality of layers each having a        metal chalcogenide composition and with a molecular formula of        MX2 (M=W and X═S), preferably with a spherical shape,    -   wherein the one or more polymer compound (B) is obtainable by        polymerizing a monomer composition comprising:        -   a) 1 to 60% by weight, preferably 2 to 50% by weight, more            preferably 2 to 40% by weight, most preferably 3 to 35% by            weight, of the one or more functional monomer as            component a) based on the one or more polymer compound (B);            and        -   b) 10 to 99% by weight, preferably 20 to 98% by weight, more            preferably 30 to 98% by weight, most preferably 35 to 97% by            weight, of the one or more alkyl (meth)acrylate monomer as            component b) based on the one or more polymer compound (B);            and        -   c) 0 to 89% by weight, preferably 10 to 80% by weight, more            preferably 20 to 70% by weight, most preferably 25 to 60% by            weight, of the reaction product of one or more ester of            (meth)acrylic acid and one or more hydroxylated hydrogenated            polybutadiene having a number-average molecular weight (Mn)            of 500 to 10,000 g/mol as component c) based on the one or            more polymer compound (B); and            wherein the weight ratio of the one or more intercalation            compound (A) to the one or more polymer compound (B) is 20:1            to 1:5, preferably 10:1 to 1:2, more preferably 5:1 to 1:1,            most preferably 4:1 to 2:1.

In a preferred embodiment the amount of monomer a), b) and optionally c)of the monomer composition sum up to 100% by weight.

According to the invention it is preferred that the mixture comprisingthe one or more intercalation compound (A) and the one or more polymercompound (B) further comprises a solvent (C), preferably wherein thesolvent is a base oil, an organic solvent or a mixture thereof.

The solvent (C) can be a base oil, selected from the list consisting ofan API Group I base oil, an API Group II base oil, an API Group III, anAPI Group IV base oil and an API Group V base oil or a combinationthereof.

The solvent (C) can be an organic solvent selected from the list ofalkanes, aromatic hydrocarbons, esters, ethers or a combination thereof.

It is preferred, that the mixture comprises 30 to 99.9%, more preferably50 to 99%, most preferably 70 to 99% by weight of solvent (C).

According to a preferred embodiment of the method for manufacturing thepolymeric-inorganic nanoparticle composition, the mixture of one or moreintercalation compound (A), the one or more polymer compound (B) and thesolvent (C) is milled via a ball mill process. Preferably, the ball millprocess comprises introducing 0.1 to 10 kWh per kg, preferably 1 to 5kWh per kg, more preferably 1.5 to 3 kWh per kg energy into the mixture.

In another preferred embodiment of the method for manufacturing thepolymeric-inorganic nanoparticle composition, the mixture of one or moreintercalation compound (A), the one or more polymer compound (B) and thesolvent (C) is milled using an ultrasound equipment having between 10 to1000 W, preferably 50 to 800 W and more preferably 100 to 500 W power.Preferably, the composition is milled for 1 to 240 minutes, morepreferably for 10 to 180 minutes and even more preferably for 30 to 150minutes to achieve a stable polymeric-inorganic nanoparticlecomposition.

Another aspect of the invention is a method for manufacturing apolymeric-inorganic nanoparticle composition according to the invention,especially a polymeric-inorganic nanoparticle composition as describedabove. The inventive method comprises the steps of:

-   -   (a) providing one or more intercalation compound (A) as defined        herein;    -   (b) providing one or more polymer compound (B) as defined        herein;    -   (c) preferably, providing a solvent (C) as defined herein;    -   (d) combining at least the one or more intercalation        compound (A) and the one or more polymer compound (B) to obtain        a mixture, preferably combining at least the one or more        intercalation compound (A), the one or more polymer compound (B)        and the solvent (C) to obtain a mixture; and    -   (e) milling the mixture.

According to this invention, the milling step (e) is defined by aresulting change of particle size distribution of thepolymeric-inorganic nanoparticle composition measured using dynamiclight scattering technology (DLS).

The milling technology according to the invention described in step (e)can be milling via high pressure homogenization, high shear mixing,ultrasonic sound, ball milling, ultrahigh-pressure technology (jet mill)or a combination thereof. Indeed, the particle size of the agglomeratesis reduced using these milling technologies.

According to a preferred embodiment of the method for manufacturing thepolymeric-inorganic nanoparticle composition, the mixture of one or moreintercalation compound (A), the one or more polymer compound (B) and thesolvent (C) is milled via a ball mill process.

By using a ball mill, the onion like particles (intercalation compound(A)) will break apart and the individual layers, sheets of layers orfragments will be dispersed by the dispersing agent resulting in adispersion with improved stability (see FIG. 4). The individual layers,sheets of layers or fragments show surprisingly impressive extremepressure performance in comparison with dispersion technologies whichkeep the onion shape like in the literature provided (see FIG. 3) andvery low coefficient of friction values in the boundary regime.

Use of the Polymeric-Inorganic Nanoparticle Composition According to theInvention

A further aspect of the invention is the use of the polymeric-inorganicnanoparticle composition as defined herein as an additive for alubricant composition.

The polymeric-inorganic nanoparticle composition as defined herein andthe lubricant compositions comprising the polymeric-inorganicnanoparticle composition according to the invention are favorably usedfor driving system lubricating oils (such as manual transmission fluids,differential gear oils, automatic transmission fluids andbelt-continuously variable transmission fluids, axle fluid formulations,dual clutch transmission fluids, and dedicated hybrid transmissionfluids), hydraulic oils (such as hydraulic oils for machinery, powersteering oils, shock absorber oils), engine oils (for gasoline enginesand for diesel engines) and industrial oil formulations (such as windturbine).

In a preferred embodiment according to the invention thepolymeric-inorganic nanoparticle composition improves the extremepressure performance and reduces friction of moving metal parts of anengine, a gearbox or pump of an automobile, a wind turbine, or ahydraulic system.

Formulations

Yet another aspect of the invention is a composition comprising:

-   -   (i) a base oil; and    -   (ii) a polymeric-inorganic nanoparticle composition as defined        herein.

In a preferred embodiment of the invention the base oil is selected fromthe list consisting of an API Group I base oil, an API Group II baseoil, an API Group III, an API Group IV base oil and an API Group V baseoil or a mixture of one or more of these base oils.

The formulation may be an additive formulation comprising thepolymeric-inorganic nanoparticle composition according to the inventionand a base oil as diluent. The additive formulation may, for example, beadded as an extreme pressure and/or as anti-friction additive tolubricants. Typically, the additive formulation comprises a relativelyhigh amount of polymeric-inorganic nanoparticle composition accordingthe invention.

The formulation may also represent a lubricant formulation comprisingthe polymer-inorganic nanoparticle composition according to theinvention, a base oil and optionally further additives as discussedbelow. The lubricant formulation may, for example, be used as atransmission fluid or an engine oil. Typically, the lubricantformulation comprises a lower amount of polymeric-inorganic nanoparticlecomposition according to the invention as compared to the aforementionedadditive formulation.

If the formulation is used as an additive formulation, the amount ofbase oil as component (i) preferably is 40 to 95% by weight, morepreferably 70 to 90% by weight and the amount of polymeric-inorganicnanoparticle composition as component (ii) preferably is 5 to 60% byweight, more preferably 10 to 30% by weight, based on the total weightof the formulation.

If the formulation is used as a lubricant formulation, the amount ofbase oil as component (i) is preferably 50 to 99.99% by weight, morepreferably 65 to 99.99% by weight, even more preferably 75 to 99.9% byweight, and the amount of polymeric-inorganic nanoparticle compositionas component (ii) preferably is 0.01 to 50% by weight, more preferably0.01 to 35% by weight, even more preferably 0.1 to 25% by weight, basedon the total weight of the formulation.

Preferably, the amount of components (i) and (ii) add up to 100% byweight.

The base oil to be used in the formulation preferably comprises an oilof lubricating viscosity. Such oils include natural and synthetic oils,oil derived from hydrocracking, hydrogenation, and hydro-finishing,unrefined, refined, re-refined oils or mixtures thereof.

The base oil may also be defined as specified by the American PetroleumInstitute (API) (see April 2008 version of “Appendix E-API Base OilInterchangeability Guidelines for Passenger Car Motor Oils and DieselEngine Oils”, section 1.3 Sub-heading 1.3. “Base Stock Categories”).

The API currently defines five groups of lubricant base stocks (API1509, Annex E—API Base Oil Interchangeability Guidelines for PassengerCar Motor Oils and Diesel Engine Oils, September 2011). Groups I, II andIll are mineral oils which are classified by the amount of saturates andsulphur they contain and by their viscosity indices; Group IV arepolyalphaolefins; and Group V are all others, including e.g. ester oils.The table below illustrates these API classifications.

TABLE 1 API definition of lubricant base stocks Sulphur Viscosity GroupSaturates content Index (VI) I    <90% >0.03%  80-120 II at least 90%not more than 80-120 0.03% III at least 90% not more than at least120    0.03% IV All polyalphaolefins (PAOs)       V All others notincluded in Groups I, II, III or IV (e.g. ester oils)

Further base oils which can be used in accordance with the presentinvention are Group II-III Fischer-Tropsch derived base oils.

Fischer-Tropsch derived base oils are known in the art. By the term“Fischer-Tropsch derived” is meant that a base oil is, or is derivedfrom, a synthesis product of a Fischer-Tropsch process. AFischer-Tropsch derived base oil may also be referred to as a GTL(Gas-To-Liquids) base oil. Suitable Fischer-Tropsch derived base oilsthat may be conveniently used as the base oil in the lubricatingcomposition of the present invention are those as for example disclosedin EP 0 776 959, EP 0 668 342, WO 97/21788, WO 00/15736, WO 00/14188, WO00/14187, WO 00/14183, WO 00/14179, WO 00/08115, WO 99/41332, EP 1 029029, WO 01/18156, WO 01/57166 and WO 2013/189951.

Especially for transmission oil formulations, base oils of API Group IIIand mixtures of different Group III oils are used. In a preferredembodiment, the base oil may also be a polyalphaolefin base oil or amixture of a polyalphaolefin base oil with an API Group III base oil ora mixture of API Group III base oils.

The lubricant formulation according to the invention may also contain,as component (iii), further additives selected from the group consistingof dispersants, defoamers, detergents, antioxidants, pour pointdepressants, antiwear additives, extreme pressure additives,anticorrosion additives, yellow metal passivator, friction modifiers,dyes and mixtures thereof.

Appropriate dispersants include poly(isobutylene) derivatives, forexample poly(isobutylene)succinimides (PIBSIs), including boratedPIBSIs; and ethylene-propylene oligomers having N/O functionalities.

Dispersants (including borated dispersants) are preferably used in anamount of 0 to 5% by weight, based on the total amount of the lubricantcomposition.

Suitable defoamers are silicone oils, fluorosilicone oils, fluoroalkylethers, etc.

The defoaming agent is preferably used in an amount of 0.001 to 0.2% byweight, based on the total amount of the lubricant composition.

The preferred detergents include metal-containing compounds, for examplephenoxides; salicylates; thiophosphonates, especiallythiopyrophosphonates, thiophosphonates and phosphonates; sulfonates andcarbonates. As metal, these compounds may contain especially calcium,magnesium and barium. These compounds may preferably be used in neutralor overbased form.

Detergents are preferably used in an amount of 0.2 to 8% by weight,preferably 0.2 to 1% by weight, based on the total amount of thelubricant composition.

The suitable antioxidants include, for example, phenol-basedantioxidants and amine-based antioxidants.

Phenol-based antioxidants include, for example,octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate;4,4′-methylenebis(2,6-di-tert-butylphenol);4,4′-bis(2,6-di-t-butylphenol); 4,4′-bis(2-methyl-6-t-butylphenol);2,2′-methylenebis(4-ethyl-6-t-butylphenol);2,2′-methylenebis(4-methyl-6-t-butyl phenol);4,4′-butylidenebis(3-methyl-6-t-butylphenol);4,4′-isopropylidenebis(2,6-di-t-butylphenol);2,2′-methylenebis(4-methyl-6-nonylphenol);2,2′-isobutylidenebis(4,6-dimethylphenol);2,2′-methylenebis(4-methyl-6-cyclohexylphenol);2,6-di-t-butyl-4-methylphenol; 2,6-di-t-butyl-4-ethyl-phenol;2,4-dimethyl-6-t-butylphenol; 2,6-di-t-amyl-p-cresol;2,6-di-t-butyl-4-(N,N′-dimethylaminomethylphenol);4,4′thiobis(2-methyl-6-t-butylphenol);4,4′-thiobis(3-methyl-6-t-butylphenol);2,2′-thiobis(4-methyl-6-t-butylphenol);bis(3-methyl-4-hydroxy-5-t-butylbenzyl) sulfide;bis(3,5-di-t-butyl-4-hydroxybenzyl) sulfide;n-octyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate;n-octadecyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate;2,2′-thio[diethyl-bis-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],etc. Of those, especially preferred are bis-phenol-based antioxidantsand ester group containing phenol-based antioxidants.

The amine-based antioxidants include, for example,monoalkyldiphenylamines such as monooctyldiphenylamine,monononyldiphenylamine, etc.; dialkyldiphenylamines such as4,4′-dibutyldiphenylamine, 4,4′-dipentyldiphenylamine,4,4′-dihexyldiphenylamine, 4,4′-diheptyldiphenylamine,4,4′-dioctyldiphenylamine, 4,4′-dinonyldiphenylamine, etc.;polyalkyldiphenylamines such as tetrabutyldiphenylamine,tetrahexyldiphenylamine, tetraoctyldiphenylamine,tetranonyldiphenylamine, etc.; naphthylamines, concretelyalpha-naphthylamine, phenyl-alpha-naphthylamine and furtheralkyl-substituted phenyl-alpha-naphthylamines such asbutylphenyl-alpha-naphthylamine, pentylphenyl-alpha-naphthylamine,hexylphenyl-alpha-naphthylamine, heptylphenyl-alpha-naphthylamine,octylphenyl-alpha-naphthylamine, nonylphenyl-alpha-naphthylamine, etc.Of those, diphenylamines are preferred to naphthylamines, from theviewpoint of the antioxidation effect thereof.

Suitable antioxidants may further be selected from the group consistingof compounds containing sulfur and phosphorus, for example metaldithiophosphates, for example zinc dithiophosphates (ZnDTPs), “OOStriesters”=reaction products of dithiophosphoric acid with activateddouble bonds from olefins, cyclopentadiene, norbornadiene, α-pinene,polybutene, acrylic esters, maleic esters (ashless on combustion);organosulfur compounds, for example dialkyl sulfides, diaryl sulfides,polysulfides, modified thiols, thiophene derivatives, xanthates,thioglycols, thioaldehydes, sulfur-containing carboxylic acids;heterocyclic sulfur/nitrogen compounds, especiallydialkyldimercaptothiadiazoles, 2-mercaptobenzimidazoles; zincbis(dialkyldithiocarbamate) and methylene bis(dialkyldithiocarbamate);organophosphorus compounds, for example triaryl and trialkyl phosphites;organocopper compounds and overbased calcium- and magnesium-basedphenoxides and salicylates.

Antioxidants are used in an amount of 0 to 15% by weight, preferably0.01 to 10% by weight, more preferably 0.01 to 5% by weight, based onthe total amount of the lubricant composition.

Suitable anticorrosion additives are succinic acid partial esters,succinic acid partial ester amine salts, organic carboxylic acids,sulfonates and suitable yellow metal passivators are thiadiazoles,triazoles and high molecular phenolic antioxidants.

Anticorrosion additives are used in an amount of 0 to 5% by weight,yellow metal passivators are used in an amount of 0 to 1% by weight, allamounts based on the total weight of the lubricant composition.

The pour-point depressants include ethylene-vinyl acetate copolymers,chlorinated paraffin-naphthalene condensates, chlorinatedparaffin-phenol condensates, polymethacrylates, polyalkylstyrenes, etc.Preferred are polymethacrylates having a weight-average molecular weightof from 5,000 to 200,000 g/mol.

The amount of the pour point depressant is preferably from 0.01 to 5% byweight, based on the total amount of the lubricant composition.

The preferred antiwear and extreme pressure additives includesulfur-containing compounds such as zinc dithiophosphate, zincdi-C₃₋₁₂-alkyldithiophosphates (ZnDTPs), zinc phosphate, zincdithiocarbamate, molybdenum dithiocarbamate, molybdenum dithiophosphate,alkyl dithiophosphate, disulfides, sulfurized olefins, sulfurized oilsand fats, sulfurized esters, thiocarbonates, thiocarbamates,polysulfides, etc.; phosphorus-containing compounds such as phosphites,phosphates, for example trialkyl phosphates, triaryl phosphates, e.g.tricresyl phosphate, amine-neutralized mono- and dialkyl phosphates,ethoxylated mono- and dialkyl phosphates, phosphonates, phosphines,amine salts or metal salts of those compounds, etc.; sulfur andphosphorus-containing anti-wear agents such as thiophosphites,thiophosphates, thiophosphonates, amine salts or metal salts of thosecompounds, etc.

The antiwear agent may be present in an amount of 0 to 3% by weight,preferably 0.1 to 1.5% by weight, more preferably 0.5 to 0.9% by weight,based on the total amount of the lubricant composition.

The preferred friction modifiers may include mechanically activecompounds, for example molybdenum disulphide, graphite (includingfluorinated graphite), poly (trifluorethylene), polyamide, polyimide;compounds which form adsorption layers, for example long-chaincarboxylic acids, fatty acid esters, ethers, alcohols, amines, amides,imides, phosphonates, phosphite; compounds which form layers throughtribochemical reactions, for example saturated fatty acids, phosphoricacid, boric acid esters and thiophosphoric esters, xanthogenates,sulphurized fatty acids; compounds which form polymer-like layers, forexample ethoxylated dicarboxylic acid partial esters, dialkylphthalates, methacrylates, unsaturated fatty acids, sulphurized olefinsand organometallic compounds, for example molybdenum compounds(molybdenum dithiophosphates and molybdenum dithiocarbamates MoDTC) andtheir combinations with ZnDTPs, copper-containing organic compounds.

Some of the compounds listed above may fulfil multiple functions. ZnDTP,for example, is primarily an antiwear additive and extreme pressureadditive, but also has the character of an antioxidant and corrosioninhibitor (here: metal passivator/deactivator).

The above-detailed additives are described in detail, inter alia, in T.Mang, W. Dresel (eds.): “Lubricants and Lubrication”, Wiley-VCH,Weinheim 2001; R. M. Mortier, S. T. Orszulik (eds.): “Chemistry andTechnology of Lubricants”.

Preferably, the total concentration of the one or more additives (iii)is up to 20% by weight, more preferably 0.05% to 15% by weight, morepreferably 5% to 15% by weight, based on the total weight of thelubricant formulation.

Preferably, the amounts of (i) to (iii) add up to 100% by weight.

The all-in-once lubricant formulation comprising the polymeric-inorganicnanoparticle composition of the invention combines stability over thetime, as well as improved anti-weld performance and/or anti-frictionproperties as shown below in the experimental part. This approachtherefore avoids any incompatibilities between different packagecomponents, dispersing agents, and other additives in the lubricantformulation as a single additive combines all properties.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of better illustrating the advantages and properties ofthe claimed polymeric-inorganic particles object of the invention,several graphs are attached as non-limiting examples:

FIG. 1 is a diagram showing the friction reduction in % in boundaryregime.

FIG. 2 is a bar chart comparing the four ball weld results of thecomposition according to the invention with prior art compositions.

FIG. 3 is a Transmission Electron Microscope (TEM) image of an originalintercalation compound of IF-WS₂ prepared in isopropanol/water,dispersed and dried.

FIG. 4 is a Transmission Electron Microscope (TEM) image of the sameintercalation compound of IF-WS₂ after ball milling treatment accordingto the present invention, the image being taken after centrifugation andwashing with chloroform.

EXPERIMENTAL PART

The invention is further illustrated in detail hereinafter withreference to examples and comparative examples, without any intention tolimit the scope of the present invention.

Abbreviations

-   -   C₁ AMA C₁-alkyl methacrylate (methyl methacrylate; MMA)    -   C₄ AMA C₄-alkyl methacrylate (n-butyl methacrylate)    -   C₁₂₋₁₄ AMA C₁₂₋₁₄-alkyl methacrylate    -   C₁₂₋₁₅ AMA C₁₂₋₁₅-alkyl methacrylate    -   OCTMO Octyltrimethoxysilan    -   DMAPMAA N-3-Dimethylaminopropylmethacrylamid    -   f_(branch) degree of branching in mol %    -   MA-1 macroalcohol (hydroxylated hydrogenated polybutadiene        M_(n)=2,000 g/mol)    -   MM-1 macromonomer of MA-1 with methacrylate functionality    -   M_(n) number-average molecular weight    -   M_(w) weight-average molecular weight    -   NB3020 Nexbase® 3020, Group III base oil from Neste with a KV₁₀₀        of 2.2 cSt    -   NB3043 Nexbase® 3043, Group III base oil from Neste with a KV₁₀₀        of 4.3 cSt    -   NB3060 Nexbase® 3060, Group III base oil from Neste with a KV₁₀₀        of 6.0 cSt    -   VISCOBASE 5-220 VISCOBASE® 5-220 is a group V synthetic base        fluid from Evonik with a KV100 of 480 cSt    -   VISCOPLEX 14-520 defoamer    -   DI package Afton HiTec® 307 (detergent inhibitor)    -   PPD Pour point depressant    -   PDI Polydispersity index, molecular weight distribution        calculated via M_(w)/M_(n)    -   MTM Mini Traction Machine equipment

Synthesis of a Hydroxylated Hydrogenated Polybutadiene (Macroalcohol)MA-1

The macroalcohol was synthesized by anionic polymerization of1,3-butadiene with butyllithium at 20-45° C. On attainment of thedesired degree of polymerization, the reaction was stopped by addingpropylene oxide and lithium was removed by precipitation with methanol.Subsequently, the polymer was hydrogenated under a hydrogen atmospherein the presence of a noble metal catalyst at up to 140° C. and 200 barpressure. After the hydrogenation had ended, the noble metal catalystwas removed and organic solvent was drawn off under reduced pressure toobtain a 100% macroalcohol MA-1.

Table 2 summarizes the characterization data of MA-1

TABLE 2 Characterization data of used macroalcohol. Mr, [g/mol]Hydrogenation level [%] OH functionality [%] MA-1 2,000 >99 >98

Synthesis of Macromonomer MM-1

In a 2 L stirred apparatus equipped with saber stirrer, air inlet tube,thermocouple with controller, heating mantle, column having a randompacking of 3 mm wire spirals, vapor divider, top thermometer, refluxcondenser and substrate cooler, 1000 g of the above-describedmacroalcohol are dissolved in methyl methacrylate (MMA) by stirring at60° C. Added to the solution are 20 ppm of2,2,6,6-tetramethylpiperidin-1-oxyl radical and 200 ppm of hydroquinonemonomethyl ether. After heating to MMA reflux (bottom temperature about110° C.) while passing air through for stabilization, about 20 mL of MMAare distilled off for azeotropic drying. After cooling to 95° C., LiOCH₃is added and the mixture is heated back to reflux. After the reactiontime of about 1 hour, the top temperature has fallen to ˜64° C. becauseof methanol formation. The methanol/MMA azeotrope formed is distilledoff constantly until a constant top temperature of about 100° C. isestablished again. At this temperature, the mixture is left to react fora further hour. For further workup, the bulk of MMA is drawn off underreduced pressure. Insoluble catalyst residues are removed by pressurefiltration (Seitz T1000 depth filter).

Table 3 summarizes the MMA and LiOCH₃ amounts used for the synthesis ofmacromonomer MM-1

TABLE 3 Macroalcohol, MMA and catalyst amounts for thetransesterification of the macromonomer. Macromonomer MacroalcoholAmount MMA [g] Amount LiOCH₃ [g] MM-1 MA-1 500 1.5

Preparation of Amine-Containing Copolymer According to the Invention

As described above, the polymer weight-average molecular weights weremeasured by gel permeation chromatography (GPC) calibrated usingpolymethylmethacrylate (PMMA) standards. Tetrahydrofuran (THF) is usedas eluent.

Example Polymer 1 (P1): Preparation of a Amine-Containing CopolymerAccording to the Invention

200 grams of Nexbase 3043, 11.34 grams ofn-3-dimethylaminopropylmethacrylamid (DMAPMAA), 272.21 grams of laurylmethacrylate (C₁₂₋₁₄ AMA, 5.53 grams of n-dodecyl mercaptan (n-DDM) 5.53grams of 2-Ethylhexylthioglycolate (TGEH) were charged into 2 liter,4-necked round bottom flask. The reaction mixture was stirred using aC-stirring rod, inerted with nitrogen, and heated to 90° C. Once thereaction mixture reached the setpoint temperature, 2.83 gramst-butylperoctoate was fed into the reactor over 2 hours. After 2 hoursthe mixture was heated up to 100° C. and after reaching the setpoint1.42 grams of t-butylper-2-ethylhexanoate and 1.13 grams oftert-butylperpivalate were fed in one hour. Residual monomer wasmeasured by gas chromatography to ensure good monomer conversion. Thepolymer obtained has a weight-average molecular weight M_(w) of 10,500g/mol (PMMA standard).

Example Polymer 2 (P2): Preparation of an Amine-Containing CopolymerAccording to the Invention

276 grams of 100N oil (group II oil), 16 grams of methyl methacrylate,13 grams of dimethylaminopropylmethacrylamide, 290 grams of C₁₂₋₁₅ AMA,and 0.5 grams of n-dodecylmercaptan were charged into a 2-liter,4-necked round bottom flask. The reaction mixture was stirred using aC-stirring rod, inerted with nitrogen, and heated to 110° C. Once thereaction mixture reached the setpoint temperature, 0.6 grams oftertbutyl-2-ethyleperoxyhexanoate were fed into the reactor over 3hours. After the feed was complete, the reaction was allowed to stir forone hour. Residual monomer was measured by gas chromatography to ensuregood monomer conversion. The polymer obtained has a weight-averagemolecular weight M_(w) of 157,000 g/mol (PMMA standard).

Example Polymer 3 (P3): Preparation of an Amine andMacromonomer-Containing Copolymer According to the Invention

85 grams of NB3020, 85 grams of Berylane 230SPP, 140 grams ofmacromonomer, 107 grams of butyl methacrylate, 28 grams of styrene, 13grams of lauryl methacrylate, 8 grams ofdimethylaminopropylmethacrylamide, and 1 grams of n-dodecylmercaptanwere charged into a 2-liter, 4-necked round bottom flask. The reactionmixture was stirred using a C-stirring rod, inerted with nitrogen, andheated to 115° C. Once the reaction mixture reached the setpointtemperature, 0.9 grams of tertbutyl-2-ethyleperoxyhexanoate were fedinto the reactor over 3 hours. 0.5 grams of2,2-di-(tert-butylperoxy)-butane were added in 30 minutes and 3 hoursafter the previous feed. The reaction was allowed to stir for one hour,and then an additional 132 grams of NB3020 were added to the reactor andallowed to mix for 1 hour. The polymer obtained has a weight-averagemolecular weight M_(w) of 260,000 g/mol (PMMA standard).

For the examples P1, P2 and P3, the monomer components add up to 100%.The amount of initiator and chain transfer agent is given relative tothe total amount of monomers. Table 4 below shows the monomercomposition and reactants to prepare the polymers P1, P2 and P3, as wellas their final characterization.

TABLE 4 Composition, weight-average molecular weight and PDI of polymersaccording to the present invention C₄ C₁ C₁₂₋₁₄- or C₁₂₋₁₅ MM-1 StyreneAMA AMA AMA DMAPMA f_(branch) Initiator CTA M_(w) Ex [wt %] [wt %] [wt%] [wt %] [wt %] [wt %] — [%] [wt %] [g/mol] PDI P1 — — — — 96.0 4.0 —1.9 3.9  10,500 1.61 C₁₂₋₁₄ AMA P2 — — — 5.1 90.9 4.0 — 157,000 2.31C₁₂₋₁₅ AMA P3 38.49 11.01 42.0 0.24 4.88 3.38 1.8 0.75 0.40 260,000 2.85C₁₂₋₁₄ AMA

Preparation of Polymeric-Inorganic Nanoparticle Concentrates Accordingto the Invention

Dispersion IE1:

4 g of IF-WS₂ particles are given into a solution of 14 g NB3043 oilincluding 2 g of P1 while this mixture is treated with ultrasound(ultrasound processor UP400S with 400 Watt, 24 kHz with Ti-sonotrode).After the addition is finished the dispersion is treated for 120minutes. The particle size distribution (measured in Tegosoft DEC oilusing dynamic light scattering equipment, LA-950, Horiba Ltd., Japan)shows a d50 value of 54 nm.

Dispersion IE2:

4 g of IF-WS₂ particles are given into a solution of 13.6 g NB3043 oilincluding 2.2 g of P2 while this mixture is treated with ultrasound(ultrasound processor UP400S with 400 Watt, 24 kHz with Ti-sonotrode).After the addition is finished the dispersion is treated for 120minutes. The particle size distribution (measured in Tegosoft DEC oilusing dynamic light scattering equipment, LA-950, Horiba Ltd., Japan)shows a d50 value of 71 nm.

Dispersion IE3 (with Ball Mill):

The ball mill equipment (Netzsch Laboratory Mill Micro Series, 85% ofmilling chamber filled with 0.4 mm Y-stabilized ZrO₂ balls) ispre-loaded with 245 g NB3043 oil and 35 g of P1 while the peristalticpump is set to 80 rpm and the ball mill to 1000 rpm. Afterwards, 70 g ofIF-WS₂ particles are given into this solution. The ball mill is set to arotation speed of 3500 rpm and the dispersion is treated until 1.0 kWhenergy is introduced. The particle size distribution (measured inTegosoft DEC oil using dynamic light scattering equipment, LA-950,Horiba Ltd., Japan) shows a d50 value of 47 nm.

Dispersion IE4 (with Ball Mill):

The ball mill equipment (Bachofen DynoMill, 70% of milling chamber isfilled with 0.3-0.6 mm Ce-stabilized ZrO₂ balls) is pre-loaded with143.9 g NB3043 oil and 24.1 g of P2 while the ball mill is set to 3900rpm. Afterwards, 42 g of IF-WS₂ particles are given into this solution.The dispersion is treated until 2.8 kWh energy is introduced. Theparticle size distribution (measured in Tegosoft DEC oil using dynamiclight scattering equipment, LA-950, Horiba Ltd., Japan) shows a d50value of 48 nm.

Dispersion IE5:

4 g of IF-WS₂ particles are given into a solution of 13.6 g NB3043 oilincluding 2.4 g of P3 while this mixture is treated with ultrasound(ultrasound processor UP400S with 400 Watt, 24 kHz with Ti-sonotrode).After the addition is finished the dispersion is treated for 120minutes. The particle size distribution (measured in Tegosoft DEC oilusing dynamic light scattering equipment, LA-950, Horiba Ltd., Japan)shows a d50 value of 63 nm.

Preparation of Polymeric-Inorganic Nanoparticle Concentrates asComparative Example

Dispersion CE1:

4 g of IF-WS₂ particles are given into a solution of 14.8 g NB3043 oilincluding 1.2 g of ε-Caprolactam, while this mixture is treated withultrasound (ultrasound processor UP400S with 400 Watt, 24 kHz withTi-sonotrode) for 120 minutes, respectively. The particle sizedistribution (measured in Tegosoft DEC oil using dynamic lightscattering equipment, LA-950, Horiba Ltd., Japan) shows a d50 value of1,427 nm.

Dispersion CE2:

4 g of IF-WS2 particles are given into a solution of 14.8 g NB3043 oilincluding 1.2 g of OCTMO, while this mixture is treated with ultrasound(ultrasound processor UP400S with 400 Watt, 24 kHz with Ti-sonotrode)for 120 minutes, respectively. The particle size distribution (measuredin Tegosoft DEC oil using dynamic light scattering equipment, LA-950,Horiba Ltd., Japan) shows a d50 value of 432 nm.

The table 5 below summarizes the compositions of the inventivedispersions (IE) according to the invention and the comparativedispersions (CE). The listed weight percentages are based on the totalweight of the different compositions.

TABLE 5 Comparison of dispersions according the present inventionNanoparticles Polymer Nexbase ® (A) IF-WS₂ (B) content Dispersant 3043in Example in wt % Dispersant in wt % in wt % wt %  IE1 20 P1 6 10 70 IE2 20 P2 6 11.1 68.9  IE3 20 P1 6 10 70  IE4 20 P2 6 11.1 68.9  IE5 20P3 6 12 68 CE1 20 ε- — 6 74 Caprolactam CE2 20 OCTMO — 6 74

Dynamic Light Scattering (DLS)

The particle size distribution was measured in Tegosoft DEC oil usingthe dynamic light scattering equipment LB-500 produced by Horiba Ltd.

Dynamic light scattering (DLS) is a technique in physics that can beused to determine the size distribution profile of small particles insuspension or polymers in solution. This equipment can be used tomeasure the particle size of dispersed material (inorganic nanoparticlesor polymeric spheres, e.g.) in the range from 3 nm to 6 μm. Themeasurement is based on the Brownian motion of the particles within themedium and the scattering of incident laser light because of adifference in refraction index of liquid and solid material.

The resulting value is the hydrodynamic diameter of the particle'scorresponding sphere. The values d50, d90 and d99 are common standardsfor discussion, as these describe the hydrodynamic diameter of theparticle below which 50%, 90% or 99% of the particles are within theparticle size distribution. The lower these values, the better theparticle dispersion. Monitoring these values can give a clue about theparticle dispersion stability. If the values increase tremendously, theparticles are not stabilized enough and may tend to agglomerate andsediment over time resulting in a lack of stability. Depending on theviscosity of the medium, it can be stated, that a d99 value of <500 nm(e.g. for Nexbase base oil) is an indication for a stable dispersion asthe particles are held in abeyance over time.

Determination of Weld and Friction Properties of the LubricatingComposition According to the Invention

Lubricating formulations were prepared according to weight ratios shownin Table 6 below and their friction and weld performances were testedusing two methods described below. The listed weight percentages arebased on the total weight of the different formulations.

For the sake of comparison lubricating formulations are always comparedbased on the same content of intercalation compound. Therefore,formulations named with “−1” correspond to formulations having anintercalation compound concentration of 0.1 wt %, based on the totalweight of lubricating formulation. Similarly “−2” corresponds to aconcentration of 0.5 wt % and “−3” corresponds to a concentration of 1wt %. The formulations named with “a” correspond to formulationsprepared with a fully formulated oil composition according ISO VG 68.The formulations named with “b” correspond to formulations prepared withNexbase® 3043.

Fully formulated oil composition according ISO VG 68:

-   -   79.25 wt % Nexbase® 3060 (Base oil)    -   17.4 wt % VISCOBASE® 5-220 (Base oil)    -   0.7 wt % PPD    -   2.65 wt % Afton HiTec® 307 (DI package)    -   +0.2 wt % VISCOPLEX® 14-520 (defoamer)

TABLE 6 Lubricating formulations Particle Inventive examples Comparativeexamples concentration in Fully formulated Dispersion DispersionDispersion Dispersion Dispersion formulation oil ISO VG 68 IEl IE2 IE4CE1 CE2 Formulation IE1-1a 0.1 wt % 99.5 wt % 0.5 wt % FormulationIE1-2a 0.5 wt % 97.5 wt % 2.5 wt % Formulation IE2-3a   1 wt %   95 wt %5.0 wt % Formulation IE4-3a   1 wt %   95 wt % 5.0 wt % FormulationCE1-3a   1 wt %   95 wt % 5.0 wt % Formulation CE2-3a   1 wt %   95 wt %5.0 wt %

Determination of the Improvement in Weld (Extreme Pressure) According toFour Ball Weld Test

Four ball weld tests were performed according to DIN 51350 part 2(results see FIG. 2)

Table 7 summarizes the results of the 4 ball weld test.

The reference base oil mixture, fully formulated oil ISO VG 68 welds atan average weld load of 5000 N.

Comparative Example Formulation CE1-3a represents a formulation of fullyformulated oil ISO VG 68 with addition of 5 wt % of dispersion CE1(corresponding to 1 wt % intercalation compound). Weld load was found tobe 4900 N.

Comparative Example Formulation CE2-3a represents a formulation of fullyformulated oil ISO VG 68 with addition of 5 wt % of dispersion CE2(corresponding to 1 wt % intercalation compound). Weld load was found tobe 3800 N.

Inventive Examples IE1, IE2 and IE4 contain the polymeric inorganicnanoparticles synthesized using Polymer P1 or P2 and IF-WS₂. Theparticles are well dispersed and stable in the formulation.

Inventive Example Formulation IE1-1a represents a formulation of fullyformulated oil ISO VG 68 with addition of 0.5 wt % of dispersion IE1(corresponding to 0.1 wt % intercalation compound). Weld load was foundto be 7250 N.

The measured weld load is increased by 45% compared to the fullyformulated oil ISO VG 68 reference.

Inventive Example Formulation IE1-2a represents a formulation of fullyformulated oil ISO VG 68 with addition of 2.5 wt % of dispersion IE1(corresponding to 0.5 wt % intercalation compound). Weld load was foundto be 8250 N.

The measured weld load is increased by 65% compared to the fullyformulated oil ISO VG 68 reference.

Inventive Example Formulation IE2-3a represents a formulation of fullyformulated oil ISO VG 68 with addition of 5 wt % of dispersion 1E2(corresponding to 1 wt % intercalation compound). Weld load was found tobe 7000 N.

The measured weld load is increased by 40% compared to the fullyformulated oil ISO VG 68 reference.

Inventive Example Formulation IE4-3a represents a formulation of fullyformulated oil ISO VG 68 with addition of 5 wt % of dispersion 1E4(corresponding to 1 wt % intercalation compound). Weld load was found tobe 8750 N.

The measured weld load is increased by 75% compared to the fullyformulated oil ISO VG 68 reference.

TABLE 7 Results of the weld load tests Particle Maximal concentrationweld Example in formulation load in N Formulation IE1-1a 0.1 wt % 7250Formulation IE1-2a 0.5 wt % 7000 Formulation IE2-3a   1 wt % 8250Formulation IE4-3a   1 wt % 8750 Formulation CE1-3a   1 wt % 4900Formulation CE2-3a   1 wt % 3800

The higher the weld load, the better the extreme pressure performance.The reference oil formulation reaches a weld load of 5000 N. We can seethe clear proof that the addition of polymeric-inorganic nanoparticlecomposition according to the present invention into a lubricating oilformulation improves the weld performance of the lubricating oildrastically. In comparison, the state-of-art dispersions (CE1-CE2) havelower weld load values, even lower than the reference oil formulationwithout any particles. The above experimental results show that thepolymeric-inorganic nanoparticle compositions of the invention resultsin stable intercalation compound containing lubricating oilcompositions, while maintaining or even improving the weld performanceof the treated lubricating oil compositions. This result is surprisingbecause the stability of lubricating oils with nanoparticles is limitedover time as shown by the comparative examples with lower weld loadvalues as the non-treated reference oil composition.

Determination of Shear Stability for the Inventive Dispersion IE3

Shear stability test was performed according to DIN 51350 part 6

Inventive Example contains the polymeric inorganic nanoparticlessynthesized using Polymer P1 and IF-WS₂. The particles are welldispersed and stable in the formulation.

Inventive Example Formulation IE3 with 0.25 wt % intercalation compoundcontent represents a formulation of fully formulated oil ISO VG 68 withaddition of 1.25 wt % of dispersion IE3. This formulation according tothe invention is still stable after shear test.

Determination of the Reduction in Friction Via Mini Traction Machine

The coefficient of friction was measured using a Mini traction machinenamed MTM2 from PCS Instruments following the test method described inTable 4 below. SRR refers to the Sliding Roll Ratio. This parameter wasmaintained constant during the 2 hours test and is defined as(U_(Ball)−U_(Disc))/U wherein (U_(Ball)−U_(Disc)) represents the slidingspeed and U the entrainment speed, given by U=(U_(Ball)+U_(Disc))/2.Stribeck curves for each sample were measured according to protocol inTable 8.

TABLE 8 Protocol to measure the Stribeck curves Method 1 Test Rig MTM 2from PCS Instruments Disc Highly polished stainless Steel AISI 52100 Disc diameter 46 mm Ball Highly polished stainless Steel AISI 52100Ball diameter 19.05 mm Speed 5-2,500 mm/s Temperature 100° C. Load 30NSRR 50%

According to MTM Method 1, the friction coefficient was recorded overthe complete range of speed for each blend and a Stribeck curve isobtained. The friction tests were performed according to theseconditions for the formulations listed in Table 9 and results thereofare disclosed in Table 10 below. The listed weight percentages are basedon the total weight of the different formulations.

TABLE 9 Formulations according to the invention Particle concentrationin Nexbase ® Dispersion Dispersion Dispersion formulation 3043 IE4 IE5CE1 Formulation IE4-3b 1 wt % 95 wt % 5.0 wt % Formulation IE5-3b 1 wt %95 wt % 5.0 wt % Formulation CE1-3b 1 wt % 95 wt % 5.0 wt %

To express in % the friction reduction, a quantifiable result can beexpressed as a number and is obtained by integration of the frictionvalue curves using the obtained corresponding Stribeck curves in therange of sliding speed 5 mm/s-60 mm/s using the trapezoidal rule. Thearea corresponds to the “total friction” over the selected speed regime.The smaller the area, the greater the friction-reducing effect of theproduct examined. The percentage friction reductions were calculated byusing the values of the reference base oil Nexbase® 3043, whichgenerates an area of friction of 6.32 mm/s. Positive values indicate adecrease of friction coefficients. Values in relation to the referenceoil are compiled in the table 10 (see FIG. 1).

TABLE 10 Friction reduction in boundary regime for the formulationsaccording to the invention compared to base oil Friction area Reductionof Example from 5-60 mm/s Friction in % Nexbase ® 3043 6.32 referenceFormulation IE4-3b 2.42 62 Formulation IE5-3b 2.37 62.5 FormulationCE1-3b 4.55 28

The above experimental results show that the polymeric-inorganicnanoparticle compositions of the invention are stable in the lubricatingoil composition over time and show great anti-friction performance incomparison to the oil formulation of the art. Indeed, the results of thecalculated total friction in the range of sliding speed 5 mm/s-60 mm/sclearly show that the inventive examples IE4 and IE5 have a much bettereffect with regard to the reduction in friction than the correspondingcomparative example and reference Nexbase® 3043 oil. Nexbase® 3043 isthe reference base oil. This result is surprising because the stabilityof lubricating oils with nanoparticles is limited over time as shown bythe comparative example with lower friction reduction value.

The results obtained were not foreseeable from the availabledocumentation of the state of the art. There it is referred to theintact onion shape which can roll out over the surface during tribocontact in order to reduce friction through gliding effects between thetwo surfaces moving against each other. Surprisingly, thepolymeric-inorganic nanoparticles obtained by ball milling thedispersion according to the present invention provide improvedanti-friction properties to the lubricant oil compositions, in whichthey are mixed. It has been demonstrated that the chemically modifiednanoparticles of the invention have a positive influence on frictionbehaviors, while maintaining excellent stability over a long period oftime in the lubricating oil.

1. A polymeric-inorganic nanoparticle composition, obtained by milling amixture, the mixture comprising one or more intercalation compound (A)and one or more polymer compound (B), (A) wherein the one or moreintercalation compound comprises a metal chalcogenide having molecularformula MX₂, where M is a metallic element selected from the groupconsisting of titanium (Ti), vanadium (V), chromium (Cr), manganese(Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn),zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc),ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd),hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os),iridium (Ir), platinum (Pt), gold (Au), mercury (Hg) and combinationsthereof, and X is a chalcogen element selected from the group consistingof sulfur (S), selenium (Se), tellurium (Te), oxygen (0) andcombinations thereof; and (B) wherein the one or more polymer compoundis obtainable by polymerizing a monomer composition comprising: a) oneor more functional monomer as component a) selected from the listconsisting of: a1) hydroxyalkyl (meth)acrylates; a2) aminoalkyl(meth)acrylates and aminoalkyl (meth)acrylamides; a3) nitriles of(meth)acrylic acid and other nitrogen-containing (meth)acrylates; a4)aryl (meth)acrylates, where the acryl residue in each case can beunsubstituted or substituted up to four times; a5) carbonyl-containing(meth)acrylates; a6) (meth)acrylates of ether alcohols; a7)(meth)acrylates of halogenated alcohols; a8) oxiranyl (meth)acrylate;a9) phosphorus-, boron- and/or silicon-containing (meth)acrylates; a10)sulfur-containing (meth)acrylates; a11) heterocyclic (meth)acrylates;a12) maleic acid and maleic acid derivatives; a13) fumaric acid andfumaric acid derivatives; a14) vinyl halides; a15) vinyl esters; a16)vinyl monomers containing aromatic groups; a17) heterocyclic vinylcompounds; a18) vinyl and isoprenyl ethers; a19) methacrylic acid andacrylic acid, and one or both of the components selected from the groupconsisting of: b) one or more alkyl (meth)acrylate monomer; and c) thereaction product of one or more ester of (meth)acrylic acid and one ormore hydroxylated hydrogenated polybutadiene having a number-averagemolecular weight (M_(n)) of 500 to 10,000 g/mol, and wherein the weightratio of the one or more intercalation compound (A) to the one or morepolymer compound (B) is from 20:1 to 1:5.
 2. The polymeric-inorganicnanoparticle composition according to claim 1, wherein in component b)each of the alkyl group of the one or more alkyl (meth)acrylate monomersindependently is linear, cyclic or branched and comprises from 1 to 40carbon atoms.
 3. The polymeric-inorganic nanoparticle according to claim2, wherein each of the one or more alkyl (meth)acrylate monomersindependently is b1) of formula (I):

wherein R is hydrogen or methyl, R¹ means a linear, branched or cyclicalkyl residue with from 1 to 8 carbon atoms, or b2) of formula (II):

wherein R is hydrogen or methyl, R² means a linear, branched or cyclicalkyl residue with from 9 to 15 carbon atoms, or b3) of formula (III):

wherein R is hydrogen or methyl, R³ means a linear, branched or cyclicalkyl residue with from 16 to 40 carbon atoms.
 4. Thepolymeric-inorganic nanoparticle composition according to claim 1,wherein the one or more polymer compound (B) is obtained by polymerizinga monomer composition comprising components a) and b), but not componentc), and wherein the one or more polymer compound (B) has aweight-average molecular weight (M_(w)) of from 5,000 to 300,000 g/mol.5. The polymeric-inorganic nanoparticle composition according to claim1, wherein the one or more polymer compound (B) is obtainable bypolymerizing a monomer composition comprising components a) and c), andcomponent b), and wherein the one or more polymer compound (B) has aweight-average molecular weight (M_(w)) of from 10,000 to 1,000,000g/mol.
 6. The polymeric-inorganic nanoparticle composition according toclaim 1, wherein the weight ratio of the one or more intercalationcompound (A) to the one or more polymer compound (B) is from 10:1 to1:2.
 7. The polymeric-inorganic nanoparticle composition according toclaim 1, wherein the one or more polymer compound (B) is obtainable bypolymerizing a monomer composition comprising: a) from 1 to 60% byweight, of the one or more functional monomer as component a), based onthe one or more polymer compound (B); and b1) from 0 to 50% by weight,of the one or more alkyl (meth)acrylate monomer as component b), basedon the one or more polymer compound (B); and b2) from 40 to 99% byweight, of the one or more alkyl (meth)acrylate monomer as component b),based on the one or more polymer compound (B); wherein the amount of allmonomers of the monomer composition sum up to 100% by weight.
 8. Thepolymeric-inorganic nanoparticle composition according to claim 1,wherein the one or more polymer compound (B) is obtainable bypolymerizing a monomer composition comprising: a) from 1 to 60% byweight, of the one or more functional monomer as component a), based onthe one or more polymer compound (B); and b) from 10 to 95% by weight,of the one or more alkyl (meth)acrylate monomer as component b), basedon the one or more polymer compound (B); and c) from 1 to 89% by weight,of the reaction product of one or more ester of (meth)acrylic acid andone or more hydroxylated hydrogenated polybutadiene having anumber-average molecular weight (M_(n)) of from 500 to 10,000 g/mol ascomponent c), based on the one or more polymer compound (B); wherein theamount of all monomers of the monomer composition sum up to 100% byweight.
 9. A method for manufacturing a polymeric-inorganic nanoparticlecomposition as defined in claim 1, the method comprising the steps of:(a) providing one or more intercalation compound (A); (b) providing oneor more polymer compound (B); (c) providing a solvent (C); (d) combiningat least the one or more intercalation compound (A) and the one or morepolymer compound (B) to obtain a mixture, preferably combining at leastthe one or more intercalation compound (A), the one or more polymercompound (B) and the solvent (C) to obtain a mixture; and (e) millingthe mixture.
 10. The method according to claim 9, wherein at least theone or more intercalation compound (A), the one or more polymer compound(B) and the solvent (C) are combined to obtain the mixture, and whereinthe step (e) comprises milling the mixture via a ball mill process,introducing from 0.1 to 10 kWh/kg, energy into the mixture.
 11. Anadditive for a lubricant composition comprising the polymeric-inorganicnanoparticle composition according to claim
 1. 12. A formulationcomprising: (a) a base oil; and (b) a polymeric-inorganic nanoparticlecomposition according to claim
 1. 13. The formulation according to claim12, wherein the base oil is selected from the list consisting of an APIGroup I base oil, an API Group II base oil, an API Group III base oil,an API Group IV base oil and an API Group V base oil, or a mixture ofone or more of these base oils.
 14. The formulation according to claim12, comprising (i) from 40 to 95% by weight, of base oil and (ii) from 5to 60% by weight, of the polymeric-inorganic nanoparticle composition,based on the total weight of the formulation.
 15. The formulationaccording to claim 12, comprising (i) from 50 to 99.99% by weight, ofbase oil and (ii) from 0.01 to 50% by weight, of the polymeric-inorganicnanoparticle composition, based on the total weight of the formulation.16. The polymeric-inorganic nanoparticle according to claim 2, whereineach of the one or more alkyl (meth)acrylate monomers independently isb1) of formula (I):

wherein R is hydrogen or methyl, R¹ means a linear, branched or cyclicalkyl residue with 1 to 5 carbon atoms, or b2) of formula (II):

wherein R is hydrogen or methyl, R² means a linear, branched or cyclicalkyl residue with from 12 to 15 carbon atoms, or b3) of formula (III):

wherein R is hydrogen or methyl, R³ means a linear, branched or cyclicalkyl residue with from 16 to 30 carbon atoms.
 17. Thepolymeric-inorganic nanoparticle composition according to claim 1,wherein the one or more polymer compound (B) is obtained by polymerizinga monomer composition comprising components a) and b), but not componentc), and wherein the one or more polymer compound (B) has aweight-average molecular weight (M_(w)) of from 10,000 to 200,000 g/mol.18. The polymeric-inorganic nanoparticle composition according to claim1, wherein the one or more polymer compound (B) is obtainable bypolymerizing a monomer composition comprising components a) and c), andcomponent b), and wherein the one or more polymer compound (B) has aweight-average molecular weight (M_(w)) of from 200,000 to 500,000g/mol.
 19. The polymeric-inorganic nanoparticle composition according toclaim 1, wherein the weight ratio of the one or more intercalationcompound (A) to the one or more polymer compound (B) is from 4:1 to 1:2.20. The polymeric-inorganic nanoparticle composition according to claim1, wherein the one or more polymer compound (B) is obtainable bypolymerizing a monomer composition comprising: a) from 2 to 40% byweight, of the one or more functional monomer as component a), based onthe one or more polymer compound (B); and b1) from 0 to 10% by weight,of the one or more alkyl (meth)acrylate monomer as component b), basedon the one or more polymer compound (B); and b2) 65 to 97% by weight, ofthe one or more alkyl (meth)acrylate monomer as component b), based onthe one or more polymer compound (B); wherein the amount of all monomersof the monomer composition sum up to 100% by weight.